Discipline & habits
How long does it take to form a habit? Not 21 days
The 21-day rule comes from a self-help book, not a study. The best-known study found a median of 66 days, and anything from 18 to 254. What that means for a new routine.
Discipline & habits
How habits form, why motivation fades and what keeps people going, with the numbers behind the popular claims.
Every claim links to its source. How we write