Sixty Six: One Habit
66 days. No streaks.
Only for iPhone
$3.99
iPhone
Built on what the research actually found: 66 days, not 21. One habit at a time, no streaks, and reminders that stop for good on the day it's yours.
It takes 66 days, not 21.
The 21-day rule comes from a 1960 book by a plastic surgeon, describing how long his patients took to adjust to their new face in the mirror. It was never a study, and it was never about habits.
In 2010, researchers at University College London followed 96 people building real daily habits. Among those whose data fit the model, the median time for a behaviour to become automatic was 66 days. The range ran from 18 days to over 250.
Sixty Six is built on that finding, and on one sentence buried in it: missing a single day did not materially affect the process.
So this app has no streaks. Nothing to break, nothing to protect, nothing that punishes you for a Tuesday you were ill.
ONE HABIT AT A TIME
You can't add a second. The constraint is the point — the research is about one behaviour becoming automatic, not about managing a list of them.
THE ORB IS THE PROGRESS BAR
There is no percentage anywhere. Instead there's a single sphere that grows as you show up: small and dim on day one, filling most of the screen by day sixty-six. It breathes. You learn to read it without being told.
On the day it's yours, it fills the screen entirely, tells you three true things, and settles into your archive.
WHAT IT DOESN'T HAVE
- No streaks. The number counts days you showed up, and it only goes up.
- No statistics. No completion rate, no charts, no longest run — every one of those is a way of scoring you against yourself.
- No account. No sign-up, no email, no password.
- No ads. You bought it once.
- No gamification. No points, no badges, no levels, no confetti.
REMINDERS THAT KNOW WHEN TO STOP
One a day while you're building. Miss a few and they slow down instead of piling up; after a week they drop to once a week. And the day after you miss one, the reminder tells you the truth: missing one day doesn't undo anything.
On day 66 they stop for good. Sixty Six will not ask you to start another one.
ALSO
- A home screen and Lock Screen widget, so the orb exists without opening the app
- Six colour worlds, chosen from what you type
- Syncs privately through your own iCloud account — nothing reaches us, ever
- Works completely offline
One habit. Sixty-six days. Then it's yours.
The research: Lally, van Jaarsveld, Potts & Wardle, "How are habits formed: Modelling habit formation in the real world", European Journal of Social Psychology, 2010.
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The developer, Alejandro Paez, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Alejandro Paez
- Size
- 2.7 MB
- Category
- Health & Fitness
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later.
- iPhone
- Languages
- English
- Age Rating
9+
- 9+
- Contains
Health or Wellness Topics
- Copyright
- © 2026 Alejandro Paez
