Does it take 21 days to form a habit? How can you tell whether a behavior is habit or not? Perhaps these are the wrong questions, as they give people the impression that habits are like an on/off switch, when they most certainly are not.
Asking someone if they can jump is less relevant than asking how high they can jump. Most people can jump, but there’s a big difference between a one inch jump and Zion Williamson’s 45 inch vertical leap. Can the person with a one-inch vertical jump? Technically, yes, but not like Zion! The yes/no question fails to clarify that critical nuance, and misleads us in our quest to understand the habits in our lives.
21 Days to Form a Habit? Yes and (Mostly) No
If it takes 21 days to form a habit, it’s a weak one at best. If you do a behavior one time, you wouldn’t call it a habit, and yet it may have the initial technical framework of a habit (a neural pathway). I don’t actually know how many repetitions it requires for a neural pathway to be established, but it could be just one. For example, one study found that 10% of young people got hooked within 2 days of smoking their first cigarette (source). That’s some fast brain highway construction!
So let’s not limit our idea of habit to only “firmly established, strong habits.” Let’s acknowledge that it is a wide spectrum that begins with the first experiences of a new behavior. From there, it can wither away, become a core part of a person’s life, or somewhere in between. So the important question becomes: how can you ascertain a habit’s current strength?
How to Measure a Habit’s Strength
To test a habit’s strength, you must do the opposite of what you’d do to test your physical strength. Let me explain.
If you want to find out how strong you are, what do you do? You go to the weight room, load a barbell with weight, and (safely) see how much you can lift in various exercises. You put the muscles to the test. Eventually, you’ll figure out your one rep max, which puts a number on your strength. Habits are different.
Habits are very much like riding a bike. you learn them, and get better at the process. At the risk of framing it negatively, habit systems are very much like training wheels or your dad holding onto you as you ride. I should mention that training wheels and parental assistance are very helpful when learning to ride a bike! But if you never take the training wheels off, how do you know you can ride on your own?
Consciously forcing a behavior tells us nothing about its habit status. All of that conscious effort masks its subconscious strength!
When we follow habit programs or purposefully guide/alter our behavior, we aren’t relying on habit strength, but instead on a combination of intention, strategy, planning, motivation, and willpower. If managed effectively, these efforts can simulate habitual behavior for a very long time. My books Mini Habits and Elastic Habits are designed to work forever without the power of habit. But none of that tells us how strong our habits are right now.
Over time, of course, simulated habitual behavior can become actual habitual behavior, because the brain will learn the behavioral pattern. And getting a behavior to become a strong habit is the plan, because habits are unequivocally easier and more energy-efficient to do than non-habitual things.
Since my systems have been so effective for me, I like to periodically take breaks from them to see my progress. In other words, I could follow the system forever, and I’m getting the right things done each day, but I want to see what my behavior would be like without the, uh, training wheels. By taking a break, I get to see how entrenched the habit is, and how much the system was helping me.
Habit Strength Varies… a Lot
Imagine two people doing 10 push-ups a day for a full year. They could have completely different habit strength for doing push-ups at the end of the year. One might have bad memories and associations with exercise as the other enjoys the challenge. That’ll do it. Position association is the miracle grow or steroids of habit development. The more you enjoy the behavior, the more your brain will want to repeat it. This is why I design fun and non-threatening habit systems. It has a real impact on people’s success.
If it actually took 21 days to form a habit, both push-up participants would be done in 21 days. But that’s nowhere near reality. How many people have done something for 21 days and then stopped shortly after? Too many to count!
Habit development is essentially a process of becoming less emotional and more methodical about a behavior. But before the habit takes hold, how we feel about the behavior will affect the way and speed in which it integrates into the brain.
With all of that said, the way to know the strength of a habit is to stop planning the behavior. Set yourself free to do whatever you want in that area. Don’t track it. Don’t require it. Just let your natural interest pull you into it or take you away from it. I’m not saying to avoid it, just to let your natural inclination take over, because that is the essence of habit. Habits are simply powerful subconscious preferences that we develop over time (sometimes purposefully and sometimes not).
Your results may be different for each behavior, and here are a few possible scenarios that will help you determine about where you’re at. These are specific points in a wide spectrum, so you might find yourself between these.
Strong Habit: You keep doing the behavior daily, just as consistently as before. Not doing the behavior feels wrong in a way or makes your day feel incomplete.
Moderate Habit: You continue to do the behavior for 1-4 weeks, but maybe at a lesser capacity. You might gradually move away from it and possibly stop altogether after a while. If this happens, the transition from doing it every day to not doing it seems kind of fuzzy rather than abrupt, because that neural pathway will gradually weaken.
Weak Habit: You stop doing the habit suddenly without returning to it (probably within two weeks). You drop the behavior the moment it became optional because that “hook” was never really established.
The fascinating thing to me is that time spent doing a behavior has not the most important factor in my experience.
My Experience
When I took the training wheels off, I stopped reading. I’ve found I will basically never read books unless I am following a system to make myself do it. I don’t mind reading books and mostly enjoy reading. But I can (and have) read daily for years, only to stop the instant I make it optional. And the reason is negative association.
I have deep-rooted emotional angst about being “forced” to read things in school throughout childhood. It felt like a threat to my fiercely independent nature. In other words, I have a powerful negative association with reading books (not social media, unfortunately) that is rooted in my childhood. It has made my brain quite resilient to accepting the reading habit.
It’s important to note that despite what I’ve just said, I’ve made incredible progress in my reading habit. While I may need those habit training wheels to read now, my habitual background was active repulsion to reading and fierce resistance. Now I read multiple books every year. Going from repulsion to weak interest is a massive improvement. Even with the time I’ve spent on this area, it remains weaker than the other two habits I focus on the most, writing and exercise.
Framing Is Important for Habits
My exercise struggles have changed. It used to be that I never wanted to exercise. My new struggle is that I exercise hard, and my back rebels against me. This has taught me something fascinating—it’s not your objective experience that determines habitual learning speed, it’s about your perception of the behavior.
While reading is a weak habit for me, exercise has developed into a strong one, mostly limited by my body. I can stop tracking exercise for however long and still do it daily. You could say I have a good relationship with it, that I appreciate it on both a conscious and subconscious level.
Pitting reading against exercise, exercise has been objectively more painful in the short-term. Multiple times I’ve overdone it on particular exercises or perhaps had bad form, resulting in injury or debilitating back pain and headaches. But my experiences with exercise growing up are some of my fondest memories, such as playing basketball or football with friends, which has helped me transition into more “pure work” forms of exercise like lifting weights.
I get asked a lot about when a behavior is habit, how do you know, and so on. I’ve already written about “the signs of habit” in Mini Habits, but I wanted to add this post as a supplement to it. If you truly want to know how strong your habit is, remove the framework that supports your behavior. Take those training wheels off and see if your training paid off.
If your habit is strong—this has happened to me—you will forget that you aren’t requiring yourself to do it. You’ll think, “Oh, it’s time to work out.” And then you’ll do it. That’s how you know a habit is strong. If instead you just forget about the behavior and drop it quickly, it’s a weak or non-existent habit. And there’s plenty of possibilities between those extremes.
Habit is a spectrum of behavioral preference. To find out how strong it is, remove the formalities and let your natural preferences take over. You will quickly see what your strongest habits are. It’s as simple as that!
Final Note
This habit strength test works best for habits built with the flexibility of the Mini Habits or Elastic Habits daily cue. This is a non-traditional way of building a habit that gives you the entire day (without a specific cue) to complete your habit. If you build a traditional habit (“Do X at 4:30 PM”) and remove that 4:30 PM trigger, then of course the habit will be weakened considerably or die, because you’ve killed its one and only root. But that’s why I don’t like building habits that way in the first place.
I’m not schedule-oriented and I want my good habits to be as strong as bad habits, which are strong because they have multiple triggers. Smokers don’t smoke only when they see a giraffe, they smoke because it’s the weekend, because they’re eating, gambling, drinking, bored, stressed, or anxious, and so on. Multiple triggers create multiple roots and make a habit harder to kill.
As for why you would want to do this test, well, it gives you information. With this information, I know that I need to use a system if I am going to read books, but that I’ll be fine without tracking daily exercise. That’s helpful, and gives me the opportunity to optimize my tracking efforts.
