We've all heard the old saying: "It takes 21 days to form a habit." Sounds simple, right? But science tells a different story. Real and lasting change usually takes a little longer—on average, about 66 days.

Science 66 days ago

In 2009, Phillippa Lally and her team at University College London studied how people form new habits. Participants chose a small daily activity (such as drinking more water or exercising) and tracked it over time.

The results? On average, it took 66 days before the new behavior started to feel automatic.

This doesn't mean that every habit solidifies exactly on day 66. Some people formed a habit in as little as 18 days, while others took up to 254 days. However, 66 days proved to be the average sweet spot—long enough for the brain to adapt, yet short enough to feel achievable.

Why so long?

Habits are essentially mental shortcuts. Initially, the brain must consciously recall a new activity. With repetition, this effort decreases until the behavior becomes almost second nature. Imagine walking on grass: the more times you walk the same path, the clearer and easier it becomes.

What does this mean to you?

• Be patient. If a habit doesn't stick after a couple of weeks, it doesn't mean you've failed—your brain just needs more time.

• Be consistent. Daily repetition trains your brain. Missing a day occasionally won't ruin the process, but consistency is key.

• Think long-term. 66 days is about creating lasting change, not chasing quick fixes.

Key message

Lasting change isn't about flipping a switch—it's about consistent, repeated action. Give yourself about two months to practice, and you'll notice new habits starting to feel natural.