Chances are, you’ve heard somewhere that it takes 21 days to create a new habit. Or 28. Or split the difference and call it 24.5.
Where does this information come from? Apparently, out of thin air. You see, there is no basis for the claim that it takes a certain number of days to form a new habit.
We know intuitively that repetition is important. If you’ve ever moved your wastebasket from one side of your desk to the other, you (if you’re like me) probably threw papers onto the floor where the wastebasket used to be, and kept doing it for some time. But after a while, it became automatic to toss your trash to the other side, the new location. And now it would seem odd to go back to the old habit.
But here’s something cool: researchers really have studied the question of how long it takes to change habits. And the answer is? It depends.
Some habits take just a few weeks. Others take much longer. In one study the time to change a habit from non-existent to automatic ranged from 18 days to over five months. The average was 66 days. (Here, by “making a habit change” I mean it’s easier to do the action than not to. That’s how you know that a habit has taken hold, when it’s feels weird not to do it.)
And the time varies depending on how complex the behavior is, how difficult it is, and how important the habit change is to YOU. The more motivated you are, the more quickly the habit is likely to feel automatic. Makes sense, right? It’s easier to get into the habit of drinking a glass of water when you wake up than it is to get up and run three miles. But even small habits like that glass of water can take over two months to become established.
So what are the lessons here? First, not to become discouraged if the desired behavior doesn’t become automatic right away. It takes time to train the brain. Remember that the average time was over two months. And while the occasional slip wasn’t fatal, consistent daily repetition gives the shortest time to that easy place where the behavior becomes automatic and it’s harder not to do the behavior than it is to do it.
(For more information on the study I’ve described, see: Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W. and Wardle, J. (2010), How are habits formed: Modelling habit formation in the real world. Eur. J. Soc. Psychol., 40: 998–1009. doi: 10.1002/ejsp.674