We’ve all heard the oft-repeated myth that it takes 21 days to form a habit. But it’s just that—a myth, started when plastic surgeon Maxwell Maltz first noticed that it took his patients a minimum of about 21 days to get used to a new feature—or as he wrote in his book Psycho-Cybernetics, “These, and many other commonly observed phenomena tend to show that it requires a minimum of about 21 days for an old mental image to dissolve and a new one to jell.”
As his observation got repeated, we dropped some of the details (like “minimum”) and concluded that it takes exactly 21 days to form a new habit or break an old one.
So how long does it really take to eat healthier, stop smoking, or start working out regularly? In a study published in the european Journal of Social Psychology, 96 volunteers chose an eating, drinking, or activity behavior to do daily in the same context for 12 weeks.
The time it took to make that behavior a habit? 66 days on average. But it ranged across participants from 18 to 254 days—and the study’s researcher stressed that context is important, telling University College London, “To create a habit you need to repeat the behaviour in the same situation. It is important that something about the setting where you perform the behaviour is consistent so that it can cue the behaviour. If you choose a context cue, for example after lunch, we don’t think that it matters if you eat lunch at different times in the day.”
And even gaining a new good habit doesn’t get rid of the bad one, she says. “New habits do not stop the old habits from existing; they just have to become stronger influences on behaviour.”
Have you ever broken a habit or formed a new one? How long did it take you?