A streak reward pays people for coming back on a run of days. It works because of three things researchers have measured: people speed up as a goal gets close, progress they already have feels worth protecting, and a visible run of days becomes a goal of its own. It also fails for a reason researchers have measured: when one missed day wipes out the run, many people stop altogether.

We have just added a daily streak to GrowApps, so we had to decide where we stand on all of this. Below is the research, the rules we picked and why, and a checklist you can use if you want a streak in your own app.

The GrowApps daily streak in short

  • Use your daily credits on 7 days out of 9 and GrowApps adds 10 bonus credits to your account.
  • A day counts once you have used as many credits that day as your plan gives you free each day: 1 on Free, 2 on Standard, 5 on Pro. Any credits count, not only the free ones.
  • Days follow your own clock: the same local day your free daily credits refresh on.
  • Two of the nine days are spare. Missing a day does not reset anything.
  • The 10 bonus credits never expire.
  • When a round ends, won or not, the next day you use your daily credits starts a new one. There is no limit on how many rounds you can win.
  • People who were already building every day when the streak launched did not start from zero. The days they had already built on counted.

Why streaks work

Goals pull harder as they get close

In 1932 the psychologist Clark Hull noticed that rats in a maze ran faster the closer they got to the food at the end. He called it the goal gradient. In 2006 Ran Kivetz, Oleg Urminsky and Yuhuang Zheng tested it on people with a café reward card: buy 10 coffees, get one free. Members bought coffee more often the closer they got to the free one. They also found that a 12 stamp card that came with 2 bonus stamps already on it was filled faster than a plain 10 stamp card, even though both needed 10 purchases.

For a streak, this means the last days of a round have the most pull. It only works if people can see how far they still have to go.

Progress you already have feels worth protecting

Joseph Nunes and Xavier Drèze handed car wash customers one of two loyalty cards. Both needed 8 washes for a free one. One card had 8 empty spaces. The other had 10 spaces with 2 already stamped. By the end of the study, 19% of the first group had earned their free wash, against 34% of the group that started with two stamps. They called it the endowed progress effect: the same goal feels closer, and gets finished more often, when you have already started.

A visible streak becomes a goal of its own

Jackie Silverman and Alixandra Barasch ran seven studies on streaks shown in activity logs, the row of checkmarks a fitness or language app shows you. People did more of an activity when their log showed an unbroken streak than when it showed a broken one, even when their actual past activity was the same. The unbroken run itself became something to keep going.

Why most streaks lose people

The same studies carry the warning. When the log showed a broken streak, people did less, and the drop was larger when they blamed themselves for the break. It was smaller when the streak could be repaired.

An all or nothing streak, where one missed day sends you back to zero, turns every busy day into a failure you caused, with no way to repair it. That is the opposite of what this research points to.

There is a second reason to be gentle. Hengchen Dai, Katherine Milkman and Jason Riis found that people are more likely to start working on a goal right after a fresh start, such as a new week, a new month or a birthday: Google searches for "diet", gym visits and goal commitments all rose after those dates. A new round can be one of those fresh starts, as long as it does not open with a lecture about the last one.

How we designed the GrowApps streak, rule by rule

Count a day of real use, not a tap. A day counts when you use your daily credits, which means you actually built or changed something. A streak for opening the app would reward the wrong thing.

Seven of nine, not seven in a row. Two spare days mean one busy day does not cost you the week. The streak bends instead of breaking.

A round you can see. Every round is nine days with a clear end, so the Home screen and the daily email can show exactly where you are: which days counted, which day is today, and how many are left. The goal gradient needs a visible distance to work with.

A reward worth having, with no second deadline. A first build of an app on GrowApps uses about 4 credits on average, so 10 bonus credits pay for real work. They never expire, so the prize does not turn into another clock.

Start people with the progress they earned. When we launched, some people were already building every day. Their recent days counted from the start, so their first email told them how close they already were. Unlike the pre-stamped car wash card, nothing was made up: every day on their track is a day they really built.

End a round kindly. When a round can no longer be won, the email says the credits are all still there and that the next streak can start today. The next day you use your daily credits is day 1 of a new round.

A checklist for a streak in your own app

If you want a streak in your own app, these are the questions we would answer first:

  1. Which action delivers value? Count that, not app opens.
  2. Whose day is it? Use each person's own time zone, or people who build late at night lose days at a midnight that is not theirs.
  3. How many misses do you forgive? Spare days or a repair option keep one bad day from ending everything.
  4. Can people see the distance left? Show the days done and the days to go.
  5. Is the reward worth something, and does it last? A reward that expires soon becomes one more deadline.
  6. Can you honestly give a head start? Real past activity is the best kind of endowed progress.
  7. What happens after a miss? Point at the next start, not at the failure.

If you build with GrowApps, you can describe rules like these in plain words in the chat and ask for a streak in your app.

Frequently asked questions

How does the GrowApps daily streak work?

Use your daily credits on 7 days within a 9 day round and GrowApps adds 10 bonus credits to your account. The round starts on the first day you use your daily credits, and two of its nine days are spare.

What counts as a day in the GrowApps streak?

A day counts once you have used as many credits that day as your plan gives you free each day: 1 credit on Free, 2 on Standard and 5 on Pro. It does not matter which credits you use. Days follow your own local time.

What happens if I miss a day?

Nothing resets. Every round has two spare days. A round only ends early when you miss a third day, and then the next day you use your daily credits starts a new one.

Do the streak bonus credits expire?

No. The 10 bonus credits never expire.

Can I win the streak more than once?

Yes. After a round ends, the next day you use your daily credits starts a new round, and there is no limit on how many you can win.

Is the daily streak on the Free plan too?

Yes. On the Free plan a day counts once you use 1 credit that day.

Why do streaks motivate people?

Goals pull harder as they get close (the goal gradient), progress you already have feels worth protecting (the endowed progress effect), and an unbroken run becomes a goal of its own. Streaks lose people when a single miss erases all their progress and nothing can repair it.

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