It takes longer than 21 days to form a habit. Here's why — and how to actually do it.

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Forming a new healthy habit can take longer than you might expect. (Getty Images)
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If you made a New Year’s resolution, chances are it centers around forming a new habit. And, as most of us know, the pursuit of taking on a new habit is where resolutions go to die. (Sorry, too soon?) Why is that? Why can’t your first week of enthused morning walks march solidly into week two? Why is it so difficult to say no to doom scrolling and yes to overriding the screen time parameters that you yourself set?

The answer is complicated, and involves understanding the definition of a habit, which (surprise!) is just as complex and difficult as creating one. Here’s what you need to know.

What exactly is a habit?

It’s not so easy to define a habit. But according to a 2015 review published in Health Psychology Review, various definitions within psychology refer to a habit as a behavior prompted automatically by a specific cue or context. “A routine, such as getting ready for bed — brushing your teeth and then flossing — are examples of habits,” Julia Baird, clinical psychologist and director of clinical operations at Lightfully Behavioral Health, tells Yahoo Life. “In this case, the cue for brushing teeth is bedtime, and the cue for flossing is the tooth brushing that precedes it. Cues are typically environmental, such as time of day or place,” and they can even be person-related, she adds.

In short, a habit doesn’t become one until it's essentially second nature. Before then, it’s simply a behavior that takes effort to complete. The only way to turn a behavior into a habit is through time and repetition. Alexandra Solomon, therapist and author of Love Every Day: 365 Relational Self-Awareness Practices to Help Your Relationship Heal, Grow and Thrive, describes habits as elements that are deeply woven into our days, which therein make them “an energetically low lift,” she explains. It’s the practicing part that people tend to have trouble with, which inhibits the habit from forming.

Why is it so hard to adopt a new habit?

This is like asking why you’re ill-equipped for leadership on day one of the job, or why you can’t automatically jump to expert mode on Guitar Hero. When setting habit-related goals, we make the mistake of assuming they should take little effort and are purely based on willpower — “should” being the keyword. “Whenever we, as therapists, say, ‘should on ourselves,’ we make a hard thing harder,” says Solomon. “Part of how we establish a new habit is by honoring that it's not easy. The fact that it’s not easy doesn't mean that we suck, it just means that we are human.”

Even if a habit seems simple or potentially enjoyable like the intention to read nightly, solidifying it will take just as much commitment as any other. “We just can't bypass the need for practice and reps,” Solomon adds. Still, impatience and self-criticism can impede progress, which prompts a vicious cycle. You might think things like: “‘Maybe I'm broken. Maybe I'm weak. Maybe I'm foolish. Maybe I'm a failure,’” Solomon says. Those negative thoughts make the energetic lift of habit forming even heavier, “like wind in our faces,” she says.

Then there’s the fact that, no matter how good for you new habits may be, they always bring about a sense of unfamiliarity and uncertainty, which we, as humans, don’t like, explains Dr. Dave Rabin, a neuroscientist, psychiatrist and co-founder of Apollo Neuroscience. That’s especially the case if you’re already overwhelmed by your existing setbacks. “Our bodies physiologically oppose learning new things when we’re already stressed out,” he tells Yahoo Life.

Lastly, habits are difficult to confront when the pursuit of them stems from a personal wound, trauma or an “unhealed” part of yourself, notes Solomon. Although the new habit might aim to “fix” said wound, it may end up opening it further, if only temporarily. “For example, if I want to come into a habit of working out five times a week, and I have some pretty deep and unhealed wounds around body image and worthiness, I’m going to be confronted by all of that more profoundly and differently than somebody who doesn't have the same history,” Solomon explains. “It’s not going to be easy if it requires you to confront something pretty deep and tender inside.”

What about the 21-day rule — is it a myth?

Not all habits fall under the same umbrella — meaning, they don’t all take the same amount of time to master, nor do they all require the same skill and energy to grasp. That means — despite the popular “21-day rule” — there is no magic number of days it takes to create a habit either.

The 21-day “fallacy,” as Baird calls it, came from a 1960 book written by plastic surgeon Maxwell Maltz called Psycho-Cybernetics. In observing his patients, Maltz noticed that it took “a minimum of 21 days for an old mental image to dissolve and a new one to gel,” Baird says. “There was no empirical study conducted,” she adds. “Only Maltz’s personal observations and his conclusions about what they meant.”

Since then, various research has debunked Maltz’s claim. An April 2023 study, for example, compared establishing habitual hand washing in a hospital setting to establishing a new gym routine through machine learning tracking 40 million observations and 12 million observations, respectively. Both habits not only took longer than 21 days, but their results were also completely different: The study results indicated that, on average, it takes a full six months to establish a new exercise routine, but only a few weeks, on average, to adopt regular hand washing.

An older study published in the British Journal of General Practice found that the average amount of time it takes to form a new habit is 66 days. A 2018 study found that characteristics of the individual also play a significant role in the length of time it takes to form a habit — a sentiment with which Solomon agrees. “You could line up 10 people and have them all commit to eating five servings of fruit and vegetables a day,” she says. “That's going to be a heavier lift for some and an easier lift for others,” depending on schedule, available funds, palate and more.

“We can't put all habits under one umbrella because habits hit different people in different ways, based on their constitution and the realities of their lives,” Solomon says. Plus, she adds that habits have objective — not always measurable — parameters, which makes them difficult to compare. “Anything that we want in an ongoing way, we have to choose again and again, be it subconscious or not,” she adds. “You would never say, ‘21 days to a great marriage.’”

Tips for better habit forming

If you want to create a new habit, the No. 1 tip experts have is to be patient and keep trying, even when you fail. Here are some more specific pointers:

Set yourself up for success. This is especially crucial early on. Habit forming is inherently uncomfortable, so “it’s very important to focus on understanding this and surrounding ourselves with things that make us feel safe, comfortable and calm when we're trying to learn new things,” says Rabin. “This will make it easier for us to learn them over time.”

Manage expectations. “When we set our expectations too high, we often set ourselves up for failure,” says Baird. “Start with small, actionable steps and build up from there. It may not sound as rewarding, but it actually is, because you feel the satisfaction every time you complete the behavior.”

Commit to practice. “Do it whether or not you’re motivated, but rather, simply because it’s in your calendar or it’s a thing you do,” says Solomon, like brushing your teeth or eating dinner.

Try following the “Four Laws of Behavior Change." Solomon cites James Clear’s Four Laws of Behavior Change, which are outlined in his best-selling book, Atomic Habits, as a helpful guide for habit creation. The process goes as follows.

  • Cue: Establish a cue that makes the habit obvious. For example, if the habit you’d like to establish is working out in the morning, try setting out your gym clothes in the evenings for you to notice when you wake up.

  • Craving: Make it attractive. Maybe the gym clothes are new or matching or fun, or you plan to workout with a friend.

  • Response: Make it easy — don’t overdo it at the gym and start simple.

  • Reward: Treat yourself to a post-gym smoothie or coffee.

By nature, the reward will prompt another cue, and create a feedback loop that, ideally, will help you establish your desired habit over time.