Timo — Mindful Spending
A behavioral design case study exploring why young adults spend impulsively, and how we can empower them with better financial habits.
A loop she can't break
“Sometimes I'm just browsing TikTok and see something nice. Before I even think about it, I've already bought it. It's only when the package arrives that I realize I didn't actually need it. At the start of the month my balance looks fine so I don't hesitate. By the middle of the month, I open my banking app and panic, wondering where it all went.”
Duong, 23, early-career professional
It's not that Duong lacks discipline. She tracks her spending in Excel, has tried three different finance apps and knows the 50/30/20 rule. Since she already has the tools and the knowledge, discipline was never the real problem. We had to look somewhere else.
1. Context
The three forces.
160%
Hanoi apartment prices rose 160% over the last decade. Average wages rose only 90%.
Savills, GSO, World Bank
70%
of young Vietnamese agree with the statement "I prefer to enjoy my money now rather than worry too much about the future."
UOB ASEAN 2025
91%
of Vietnamese consumers admit their purchasing decisions are influenced by social media advertising
PwC APAC 2024
There are three forces acting on the same person at the same time. First, the economy makes saving money feel completely pointless. Second, everything around you constantly pushes you to spend. And finally, your own emotions turn shopping into a way to cope with how you feel. Young professionals who are just starting their careers are stuck right in the middle of all three.
The wrong moment
There are plenty of finance apps out there, but the problem is that every single one of them steps in at the wrong time.
MoMo, Money Lover and Timo's jar feature all work after you've already spent the money. They track your spending, make reports, and send alerts at the end of the month. But what really needs to happen has to come much earlier. It needs to step in before you buy something, or right at the exact moment you're making the decision, which is when you're the most emotional.
We grouped users into four categories based on what they wanted to achieve: tracking their spending, controlling emotional buying, saving for a big goal, or learning how to invest. The emotional spending group had the most frequent and urgent problem and existing apps weren't really doing anything to help them. So that's exactly what we decided to focus on.
Limitation: With 12 participants, we can surface qualitative patterns but not generalise from them. Since the sample was concentrated in Hanoi and HCMC, we also can't claim the findings represent users in other provinces.
2. Define
Duong's loop
Persona: Duong, 23
She’s been working for a year or two, making 12 to 15 million VND a month and renting a place in Ho Chi Minh City. She knows she should be managing her money better, but she keeps falling into the exact same cycle:
You get paid and feel like you have plenty of money to spend, so you talk yourself into buying something you saw online. But by the middle of the month you're completely broke and have to cut back, until payday comes around again and it all starts over.
Root causes
Root cause 1
The total balance is a lie
When Duong opens her banking app, she just sees "money I have." She doesn't see the money she's actually free to spend. Future expenses like rent, bills, and groceries only exist in theory, so they don't feel nearly as real as the total balance she sees right in front of her.
The mechanics: present bias, hyperbolic discounting and mental accounting.
Root cause 2
At the moment of purchase, only the upside is visible
When Duong wants to buy something, she only feels the excitement of getting it. She doesn't feel what she's actually giving up, like her savings jar filling up slower or her goals getting further out of reach. None of that even crosses her mind at the moment.
The mechanics: hedonic consumption, opportunity-cost neglect and the disappearing pain of paying.
How Might We
HMW 1. How can we show Duong exactly how much money she's actually free to spend, instead of letting her feel like she has plenty of money, right after payday?
HMW 2. How can we help her clearly see the difference between what she actually needs and what she just wants, right when Duong wants to buy something?
HMW 1 led to a solution quickly while HMW 2 was harder, and our first attempt at it completely missed the point.
Our first solution was wrong
Our first idea for HMW 2 was a Timo virtual card with a strict spending limit. Duong would use this card to shop on Shopee or TikTok Shop. We would pre-load it with a fixed "free to spend" amount, and once she hit that limit, the card would decline. On paper, it worked perfectly. The timing was right because it stepped in exactly at checkout, and it was something we could actually build. So, we locked in the design and started drawing the wireframes. But then, a teammate asked one question:
"If Duong is clear-headed enough to deliberately choose the Timo virtual card instead of her usual credit card, she wasn't going to spend impulsively in the first place."
That's when we realized our idea had a huge flaw. It relied on her having self-control at the exact moment her willpower was lowest. This is why most mindful-spending apps fail. They are built for when you're calm and thinking clearly, but the actual problem only happens when you're being impulsive. Any design that expects someone to make the right choice at the peak of an impulse just doesn't work.
Reframing HMW 2
Old
How might we make Duong see what she's giving up at the moment of purchase?
New
How can we help Duong set things up ahead of time to protect herself before temptation even hits?
The core idea here is based on something called commitment devices (Thaler & Benartzi, 2004; Ariely & Wertenbroch, 2002). Basically, these are tools that let your calm self set rules to control your future self. This completely changed our whole approach. We stopped trying to design for the exact moment of impulse. Instead, we realized every helpful interaction had to happen before the urge to spend even starts.
3. Solution — Future Self Fund
Layer 1 — addresses root cause 1
Free-to-Spend anchor
When her salary arrives, Timo automatically splits it into the jars Duong set up ahead of time: Rent, Bills, Savings, and her specific goals. Her main dashboard then shows just one number: Free to Spend. Right next to it is her Daily Safe to Spend, which is just that free-to-spend amount divided by the number of days left in the month.
An iOS widget puts this on her home screen, so she doesn't even need to open the app.
Changing this anchor changes what "money I have" means to her, so every later decision is measured against this number.
THÁNG 5
HŨ MỤC TIÊU
Đà Nẵng
T7
3.000.000 / 12tr
CHI HÔM NAY
☕
Café sáng
- 45.000đ
Còn tiêu hôm nay:
103.000đ
Phép tính
Thẻ mua sắm
4.450.000
đ
tiền tự do
148.000đ/ngày
Đệm an toàn:
750.000đ
giữ riêng
Quản lý hũ chi tiêu
Tổng đang quản lý
10.550.000đ
Tiền tự do còn lại: 4.450.000đ
6 hũ đang quản lý
🏠
Chi tiêu thiết yếu
Đang quản lý
4.000.000đ
💵
Đầu tư tạo thu nhập
Đang quản lý
500.000đ
🎓
Giáo dục
Đang quản lý
1.000.000đ
💃
Giải trí
Đang quản lý
2.300.000đ
🐷
Tích lũy
Đang quản lý
2.000.000đ
🛡️
Dự phòng
Đang quản lý
750.000đ
Nạp tiền
Rút tiền
Chuyển tiền
Quét mã
Timo · BẠN CỦA HIỆN TẠI
Tháng 5
4.450.000
đ
tiền tự do
148.000đ/ngày · còn 30 ngày
Layer 2 — addresses root cause 2
Risky Window Protection
This is the layer that applies the theory of commitment device directly. It operates in three phases.
Phase A: Setup (while Duong is calm). Duong answers just one question: "When are you most likely to buy things impulsively?" She picks a time window, like 9 PM to midnight, when she usually scrolls TikTok before bed. She also chooses the savings goal she wants to be reminded of, like a trip to Europe that is currently at 18%.
Phase B: Pre-warning (two hours before). The widget changes color subtly and shows a reminder: "Your risky window starts in 2 hours. Want to lock it in for tonight?" One tap locks it in.
Phase C: Active shield (during that window). The widget replaces her "Free to Spend" amount with the name of her goal. Instead of seeing "1.2M VND left to spend," Duong sees "Europe trip, 18% complete. Every 500k = 5% closer."
The protective decision gets made in Phase A, while Duong is calm, so her later and more impulsive self runs into limits her present self already set.
Timo · BẠN CỦA TƯƠNG LAI
Sắp tới
2.140.000
đ
Còn tiêu cho 13 ngày — ~165.000đ/ngày
Còn 1h45' nữa là tới khung giờ bốc đồng của bạn.
Timo · Hũ mục tiêu
Đang bảo vệ
Đà Nẵng
Bạn còn 9.000.000đ nữa thôi · T7 tới đi rồi
3.000.000đ
/ 12.000.000đ
Layer 3 — habit reinforcement
Streak reward
Every day Duong stays within her Free to Spend limit, her streak goes up by one. If she makes it through a full week, she gets a small celebration with confetti and a visible boost on her goal jar's progress bar. While the first two features mostly help her avoid making mistakes, the streak gives her a real reason to keep going. Every day she keeps it alive feels like a small win she doesn't want to ruin.
4. Reflection
Constraints
A big part of the Develop phase went into understanding what was technically possible, and what wasn't.
OS level
We can track app usage and send push notifications. We can't read content inside other apps, see what Duong browses in Shopee or block in-app payments.
Email parsing
With user consent, we can read order confirmation emails and trigger a cancellation flow inside the 12 to 24 hour cancel window. This doesn't cover offline purchases or anything that skips email entirely.
Platform partnerships
Shopee, Lazada, and TikTok Shop earn money per transaction. They have no incentive to partner with a product built to reduce purchases.
What's next?
If we had four more weeks.
The next step would have been to usability test the setup flow with a few users, to see whether Duong completes it or drops off at Phase A.
Another step would have been to validate the risky-window assumption itself. We wanted to see whether people's self-reported impulsive hours actually matched when they transacted on Timo.
We would also want to A/B-test the anchor. We wanted to see whether "Free to Spend" or "Daily Safe to Spend" worked better as the dashboard's primary number.
The lesson.
The principle I'll carry forward.
Reframing that HMW question was easily the most important decision of the whole project. It made sure that everything we built afterward was actually tackling the right problem.
If we hadn't stopped to ask why Duong would ever choose that virtual card over her usual one, we would have spent the next few weeks polishing the completely wrong solution. That question only took about thirty minutes to come up, but it saved the rest of the project.
The biggest lesson I'll take with me to every project after this is that any solution expecting someone to make a hard choice at the exact moment they're least able to do it is solving the wrong problem.
A graduation project for the UX Foundation course. Thanks to Mr. Nguyen Vuong Chung for setting the brief and mentoring the team across all 10 weeks. Thanks also to the 12 interview participants, who shared remarkably candid stories about their finances. All participant information has been anonymised in line with UX Foundation's privacy guidelines.
Team. Tung (UX Designer & Team Lead), Huyen, Thu, Khiem.
Timo — Mindful Spending
A behavioral design case study exploring why young adults spend impulsively, and how we can empower them with better financial habits.
Role
UX Designer & Team Lead
Team
4 people
Duration
10 weeks
Platform
Mobile
Scope
Discover to Define to Develop
A loop she can't break
“Sometimes I'm just browsing TikTok and see something nice. Before I even think about it, I've already bought it. It's only when the package arrives that I realize I didn't actually need it. At the start of the month my balance looks fine so I don't hesitate. By the middle of the month, I open my banking app and panic, wondering where it all went.”
Duong, 23, early-career professional
It's not that Duong lacks discipline. She tracks her spending in Excel, has tried three different finance apps and knows the 50/30/20 rule. Since she already has the tools and the knowledge, discipline was never the real problem. We had to look somewhere else.
1. Context
The three forces.
160%
Hanoi apartment prices rose 160% over the last decade. Average wages rose only 90%.
Savills, GSO, World Bank
70%
of young Vietnamese agree with the statement "I prefer to enjoy my money now rather than worry too much about the future."
UOB ASEAN 2025
91%
of Vietnamese consumers admit their purchasing decisions are influenced by social media advertising
PwC APAC 2024
There are three forces acting on the same person at the same time. First, the economy makes saving money feel completely pointless. Second, everything around you constantly pushes you to spend. And finally, your own emotions turn shopping into a way to cope with how you feel. Young professionals who are just starting their careers are stuck right in the middle of all three.
The wrong moment
There are plenty of finance apps out there, but the problem is that every single one of them steps in at the wrong time.
MoMo, Money Lover and Timo's jar feature all work after you've already spent the money. They track your spending, make reports, and send alerts at the end of the month. But what really needs to happen has to come much earlier. It needs to step in before you buy something, or right at the exact moment you're making the decision, which is when you're the most emotional.
We grouped users into four categories based on what they wanted to achieve: tracking their spending, controlling emotional buying, saving for a big goal, or learning how to invest. The emotional spending group had the most frequent and urgent problem and existing apps weren't really doing anything to help them. So that's exactly what we decided to focus on.
Limitation: With 12 participants, we can surface qualitative patterns but not generalise from them. Since the sample was concentrated in Hanoi and HCMC, we also can't claim the findings represent users in other provinces.
2. Define
Duong's loop
Persona: Duong, 23
She’s been working for a year or two, making 12 to 15 million VND a month and renting a place in Ho Chi Minh City. She knows she should be managing her money better, but she keeps falling into the exact same cycle:
You get paid and feel like you have plenty of money to spend, so you talk yourself into buying something you saw online. But by the middle of the month you're completely broke and have to cut back, until payday comes around again and it all starts over.
Root causes
Root cause 1
The total balance is a lie
When Duong opens her banking app, she just sees "money I have." She doesn't see the money she's actually free to spend. Future expenses like rent, bills, and groceries only exist in theory, so they don't feel nearly as real as the total balance she sees right in front of her.
The mechanics: present bias, hyperbolic discounting and mental accounting.
Root cause 2
At the moment of purchase, only the upside is visible
When Duong wants to buy something, she only feels the excitement of getting it. She doesn't feel what she's actually giving up, like her savings jar filling up slower or her goals getting further out of reach. None of that even crosses her mind at the moment.
The mechanics: hedonic consumption, opportunity-cost neglect and the disappearing pain of paying.
How Might We
HMW 1. How can we show Duong exactly how much money she's actually free to spend, instead of letting her feel like she has plenty of money, right after payday?
HMW 2. How can we help her clearly see the difference between what she actually needs and what she just wants, right when Duong wants to buy something?
HMW 1 led to a solution quickly while HMW 2 was harder, and our first attempt at it completely missed the point.
Our first solution was wrong
Our first idea for HMW 2 was a Timo virtual card with a strict spending limit. Duong would use this card to shop on Shopee or TikTok Shop. We would pre-load it with a fixed "free to spend" amount, and once she hit that limit, the card would decline. On paper, it worked perfectly. The timing was right because it stepped in exactly at checkout, and it was something we could actually build. So, we locked in the design and started drawing the wireframes. But then, a teammate asked one question:
"If Duong is clear-headed enough to deliberately choose the Timo virtual card instead of her usual credit card, she wasn't going to spend impulsively in the first place."
That's when we realized our idea had a huge flaw. It relied on her having self-control at the exact moment her willpower was lowest. This is why most mindful-spending apps fail. They are built for when you're calm and thinking clearly, but the actual problem only happens when you're being impulsive. Any design that expects someone to make the right choice at the peak of an impulse just doesn't work.
Reframing HMW 2
Old
How might we make Duong see what she's giving up at the moment of purchase?
New
How can we help Duong set things up ahead of time to protect herself before temptation even hits?
The core idea here is based on something called commitment devices (Thaler & Benartzi, 2004; Ariely & Wertenbroch, 2002). Basically, these are tools that let your calm self set rules to control your future self. This completely changed our whole approach. We stopped trying to design for the exact moment of impulse. Instead, we realized every helpful interaction had to happen before the urge to spend even starts.
3. Solution — Future Self Fund
Layer 1 — addresses root cause 1
Free-to-Spend anchor
When her salary arrives, Timo automatically splits it into the jars Duong set up ahead of time: Rent, Bills, Savings, and her specific goals. Her main dashboard then shows just one number: Free to Spend. Right next to it is her Daily Safe to Spend, which is just that free-to-spend amount divided by the number of days left in the month.
An iOS widget puts this on her home screen, so she doesn't even need to open the app.
Changing this anchor changes what "money I have" means to her, so every later decision is measured against this number.
THÁNG 5
HŨ MỤC TIÊU
Đà Nẵng
T7
3.000.000 / 12tr
CHI HÔM NAY
☕
Café sáng
- 45.000đ
Còn tiêu hôm nay:
103.000đ
Phép tính
Thẻ mua sắm
4.450.000
đ
tiền tự do
148.000đ/ngày
Đệm an toàn:
750.000đ
giữ riêng
Quản lý hũ chi tiêu
Tổng đang quản lý
10.550.000đ
Tiền tự do còn lại: 4.450.000đ
6 hũ đang quản lý
🏠
Chi tiêu thiết yếu
Đang quản lý
4.000.000đ
💵
Đầu tư tạo thu nhập
Đang quản lý
500.000đ
🎓
Giáo dục
Đang quản lý
1.000.000đ
💃
Giải trí
Đang quản lý
2.300.000đ
🐷
Tích lũy
Đang quản lý
2.000.000đ
🛡️
Dự phòng
Đang quản lý
750.000đ
Nạp tiền
Rút tiền
Chuyển tiền
Quét mã
Timo · BẠN CỦA HIỆN TẠI
Tháng 5
4.450.000
đ
tiền tự do
148.000đ/ngày · còn 30 ngày
Layer 2 — addresses root cause 2
Risky Window Protection
This is the layer that applies the theory of commitment device directly. It operates in three phases.
Phase A: Setup (while Duong is calm). Duong answers just one question: "When are you most likely to buy things impulsively?" She picks a time window, like 9 PM to midnight, when she usually scrolls TikTok before bed. She also chooses the savings goal she wants to be reminded of, like a trip to Europe that is currently at 18%.
Phase B: Pre-warning (two hours before). The widget changes color subtly and shows a reminder: "Your risky window starts in 2 hours. Want to lock it in for tonight?" One tap locks it in.
Phase C: Active shield (during that window). The widget replaces her "Free to Spend" amount with the name of her goal. Instead of seeing "1.2M VND left to spend," Duong sees "Europe trip, 18% complete. Every 500k = 5% closer."
The protective decision gets made in Phase A, while Duong is calm, so her later and more impulsive self runs into limits her present self already set.
Timo · BẠN CỦA TƯƠNG LAI
Sắp tới
2.140.000
đ
Còn tiêu cho 13 ngày — ~165.000đ/ngày
Còn 1h45' nữa là tới khung giờ bốc đồng của bạn.
Timo · Hũ mục tiêu
Đang bảo vệ
Đà Nẵng
Bạn còn 9.000.000đ nữa thôi · T7 tới đi rồi
3.000.000đ
/ 12.000.000đ
Layer 3 — habit reinforcement
Streak reward
Every day Duong stays within her Free to Spend limit, her streak goes up by one. If she makes it through a full week, she gets a small celebration with confetti and a visible boost on her goal jar's progress bar. While the first two features mostly help her avoid making mistakes, the streak gives her a real reason to keep going. Every day she keeps it alive feels like a small win she doesn't want to ruin.
4. Reflection
Constraints
A big part of the Develop phase went into understanding what was technically possible, and what wasn't.
OS level
We can track app usage and send push notifications. We can't read content inside other apps, see what Duong browses in Shopee or block in-app payments.
Email parsing
With user consent, we can read order confirmation emails and trigger a cancellation flow inside the 12 to 24 hour cancel window. This doesn't cover offline purchases or anything that skips email entirely.
Platform partnerships
Shopee, Lazada, and TikTok Shop earn money per transaction. They have no incentive to partner with a product built to reduce purchases.
What's next?
If we had four more weeks.
The next step would have been to usability test the setup flow with a few users, to see whether Duong completes it or drops off at Phase A.
Another step would have been to validate the risky-window assumption itself. We wanted to see whether people's self-reported impulsive hours actually matched when they transacted on Timo.
We would also want to A/B-test the anchor. We wanted to see whether "Free to Spend" or "Daily Safe to Spend" worked better as the dashboard's primary number.
The lesson.
The principle I'll carry forward.
Reframing that HMW question was easily the most important decision of the whole project. It made sure that everything we built afterward was actually tackling the right problem.
If we hadn't stopped to ask why Duong would ever choose that virtual card over her usual one, we would have spent the next few weeks polishing the completely wrong solution. That question only took about thirty minutes to come up, but it saved the rest of the project.
The biggest lesson I'll take with me to every project after this is that any solution expecting someone to make a hard choice at the exact moment they're least able to do it is solving the wrong problem.
A graduation project for the UX Foundation course. Thanks to Mr. Nguyen Vuong Chung for setting the brief and mentoring the team across all 10 weeks. Thanks also to the 12 interview participants, who shared remarkably candid stories about their finances. All participant information has been anonymised in line with UX Foundation's privacy guidelines.
Team. Tung (UX Designer & Team Lead), Huyen, Thu, Khiem.
Timo — Mindful Spending
A behavioral design case study exploring why young adults spend impulsively, and how we can empower them with better financial habits.
Role
UX Designer & Team Lead
Team
4 people
Duration
10 weeks
Platform
Mobile
Scope
Discover to Define to Develop
A loop she can't break
“Sometimes I'm just browsing TikTok and see something nice. Before I even think about it, I've already bought it. It's only when the package arrives that I realize I didn't actually need it. At the start of the month my balance looks fine so I don't hesitate. By the middle of the month, I open my banking app and panic, wondering where it all went.”
Duong, 23, early-career professional
It's not that Duong lacks discipline. She tracks her spending in Excel, has tried three different finance apps and knows the 50/30/20 rule. Since she already has the tools and the knowledge, discipline was never the real problem. We had to look somewhere else.
1. Context
The three forces.
160%
Hanoi apartment prices rose 160% over the last decade. Average wages rose only 90%.
Savills, GSO, World Bank
70%
of young Vietnamese agree with the statement "I prefer to enjoy my money now rather than worry too much about the future."
UOB ASEAN 2025
91%
of Vietnamese consumers admit their purchasing decisions are influenced by social media advertising
PwC APAC 2024
There are three forces acting on the same person at the same time. First, the economy makes saving money feel completely pointless. Second, everything around you constantly pushes you to spend. And finally, your own emotions turn shopping into a way to cope with how you feel. Young professionals who are just starting their careers are stuck right in the middle of all three.
The wrong moment
There are plenty of finance apps out there, but the problem is that every single one of them steps in at the wrong time.
MoMo, Money Lover and Timo's jar feature all work after you've already spent the money. They track your spending, make reports, and send alerts at the end of the month. But what really needs to happen has to come much earlier. It needs to step in before you buy something, or right at the exact moment you're making the decision, which is when you're the most emotional.
We grouped users into four categories based on what they wanted to achieve: tracking their spending, controlling emotional buying, saving for a big goal, or learning how to invest. The emotional spending group had the most frequent and urgent problem and existing apps weren't really doing anything to help them. So that's exactly what we decided to focus on.
Limitation: With 12 participants, we can surface qualitative patterns but not generalise from them. Since the sample was concentrated in Hanoi and HCMC, we also can't claim the findings represent users in other provinces.
2. Define
Duong's loop
Persona: Duong, 23
She’s been working for a year or two, making 12 to 15 million VND a month and renting a place in Ho Chi Minh City. She knows she should be managing her money better, but she keeps falling into the exact same cycle:
You get paid and feel like you have plenty of money to spend, so you talk yourself into buying something you saw online. But by the middle of the month you're completely broke and have to cut back, until payday comes around again and it all starts over.
Root causes
Root cause 1
The total balance is a lie
When Duong opens her banking app, she just sees "money I have." She doesn't see the money she's actually free to spend. Future expenses like rent, bills, and groceries only exist in theory, so they don't feel nearly as real as the total balance she sees right in front of her.
The mechanics: present bias, hyperbolic discounting and mental accounting.
Root cause 2
At the moment of purchase, only the upside is visible
When Duong wants to buy something, she only feels the excitement of getting it. She doesn't feel what she's actually giving up, like her savings jar filling up slower or her goals getting further out of reach. None of that even crosses her mind at the moment.
The mechanics: hedonic consumption, opportunity-cost neglect and the disappearing pain of paying.
How Might We
HMW 1. How can we show Duong exactly how much money she's actually free to spend, instead of letting her feel like she has plenty of money, right after payday?
HMW 2. How can we help her clearly see the difference between what she actually needs and what she just wants, right when Duong wants to buy something?
HMW 1 led to a solution quickly while HMW 2 was harder, and our first attempt at it completely missed the point.
Our first solution was wrong
Our first idea for HMW 2 was a Timo virtual card with a strict spending limit. Duong would use this card to shop on Shopee or TikTok Shop. We would pre-load it with a fixed "free to spend" amount, and once she hit that limit, the card would decline. On paper, it worked perfectly. The timing was right because it stepped in exactly at checkout, and it was something we could actually build. So, we locked in the design and started drawing the wireframes. But then, a teammate asked one question:
"If Duong is clear-headed enough to deliberately choose the Timo virtual card instead of her usual credit card, she wasn't going to spend impulsively in the first place."
That's when we realized our idea had a huge flaw. It relied on her having self-control at the exact moment her willpower was lowest. This is why most mindful-spending apps fail. They are built for when you're calm and thinking clearly, but the actual problem only happens when you're being impulsive. Any design that expects someone to make the right choice at the peak of an impulse just doesn't work.
Reframing HMW 2
Old
How might we make Duong see what she's giving up at the moment of purchase?
New
How can we help Duong set things up ahead of time to protect herself before temptation even hits?
The core idea here is based on something called commitment devices (Thaler & Benartzi, 2004; Ariely & Wertenbroch, 2002). Basically, these are tools that let your calm self set rules to control your future self. This completely changed our whole approach. We stopped trying to design for the exact moment of impulse. Instead, we realized every helpful interaction had to happen before the urge to spend even starts.
3. Solution — Future Self Fund
Layer 1 — addresses root cause 1
Free-to-Spend anchor
When her salary arrives, Timo automatically splits it into the jars Duong set up ahead of time: Rent, Bills, Savings, and her specific goals. Her main dashboard then shows just one number: Free to Spend. Right next to it is her Daily Safe to Spend, which is just that free-to-spend amount divided by the number of days left in the month.
An iOS widget puts this on her home screen, so she doesn't even need to open the app.
Changing this anchor changes what "money I have" means to her, so every later decision is measured against this number.
THÁNG 5
HŨ MỤC TIÊU
Đà Nẵng
T7
3.000.000 / 12tr
CHI HÔM NAY
☕
Café sáng
- 45.000đ
Còn tiêu hôm nay:
103.000đ
Phép tính
Thẻ mua sắm
4.450.000
đ
tiền tự do
148.000đ/ngày
Đệm an toàn:
750.000đ
giữ riêng
Quản lý hũ chi tiêu
Tổng đang quản lý
10.550.000đ
Tiền tự do còn lại: 4.450.000đ
6 hũ đang quản lý
🏠
Chi tiêu thiết yếu
Đang quản lý
4.000.000đ
💵
Đầu tư tạo thu nhập
Đang quản lý
500.000đ
🎓
Giáo dục
Đang quản lý
1.000.000đ
💃
Giải trí
Đang quản lý
2.300.000đ
🐷
Tích lũy
Đang quản lý
2.000.000đ
🛡️
Dự phòng
Đang quản lý
750.000đ
Nạp tiền
Rút tiền
Chuyển tiền
Quét mã
Timo · BẠN CỦA HIỆN TẠI
Tháng 5
4.450.000
đ
tiền tự do
148.000đ/ngày · còn 30 ngày
Layer 2 — addresses root cause 2
Risky Window Protection
This is the layer that applies the theory of commitment device directly. It operates in three phases.
Phase A: Setup (while Duong is calm). Duong answers just one question: "When are you most likely to buy things impulsively?" She picks a time window, like 9 PM to midnight, when she usually scrolls TikTok before bed. She also chooses the savings goal she wants to be reminded of, like a trip to Europe that is currently at 18%.
Phase B: Pre-warning (two hours before). The widget changes color subtly and shows a reminder: "Your risky window starts in 2 hours. Want to lock it in for tonight?" One tap locks it in.
Phase C: Active shield (during that window). The widget replaces her "Free to Spend" amount with the name of her goal. Instead of seeing "1.2M VND left to spend," Duong sees "Europe trip, 18% complete. Every 500k = 5% closer."
The protective decision gets made in Phase A, while Duong is calm, so her later and more impulsive self runs into limits her present self already set.
Timo · BẠN CỦA TƯƠNG LAI
Sắp tới
2.140.000
đ
Còn tiêu cho 13 ngày — ~165.000đ/ngày
Còn 1h45' nữa là tới khung giờ bốc đồng của bạn.
Timo · Hũ mục tiêu
Đang bảo vệ
Đà Nẵng
Bạn còn 9.000.000đ nữa thôi · T7 tới đi rồi
3.000.000đ
/ 12.000.000đ
Layer 3 — habit reinforcement
Streak reward
Every day Duong stays within her Free to Spend limit, her streak goes up by one. If she makes it through a full week, she gets a small celebration with confetti and a visible boost on her goal jar's progress bar. While the first two features mostly help her avoid making mistakes, the streak gives her a real reason to keep going. Every day she keeps it alive feels like a small win she doesn't want to ruin.
4. Reflection
Constraints
A big part of the Develop phase went into understanding what was technically possible, and what wasn't.
OS level
We can track app usage and send push notifications. We can't read content inside other apps, see what Duong browses in Shopee or block in-app payments.
Email parsing
With user consent, we can read order confirmation emails and trigger a cancellation flow inside the 12 to 24 hour cancel window. This doesn't cover offline purchases or anything that skips email entirely.
Platform partnerships
Shopee, Lazada, and TikTok Shop earn money per transaction. They have no incentive to partner with a product built to reduce purchases.
What's next?
If we had four more weeks.
The next step would have been to usability test the setup flow with a few users, to see whether Duong completes it or drops off at Phase A.
Another step would have been to validate the risky-window assumption itself. We wanted to see whether people's self-reported impulsive hours actually matched when they transacted on Timo.
We would also want to A/B-test the anchor. We wanted to see whether "Free to Spend" or "Daily Safe to Spend" worked better as the dashboard's primary number.
The lesson.
The principle I'll carry forward.
Reframing that HMW question was easily the most important decision of the whole project. It made sure that everything we built afterward was actually tackling the right problem.
If we hadn't stopped to ask why Duong would ever choose that virtual card over her usual one, we would have spent the next few weeks polishing the completely wrong solution. That question only took about thirty minutes to come up, but it saved the rest of the project.
The biggest lesson I'll take with me to every project after this is that any solution expecting someone to make a hard choice at the exact moment they're least able to do it is solving the wrong problem.
A graduation project for the UX Foundation course. Thanks to Mr. Nguyen Vuong Chung for setting the brief and mentoring the team across all 10 weeks. Thanks also to the 12 interview participants, who shared remarkably candid stories about their finances. All participant information has been anonymised in line with UX Foundation's privacy guidelines.
Team. Tung (UX Designer & Team Lead), Huyen, Thu, Khiem.