The 21/90 rule – A myth or the secret to self-improvement?

We like rules. We like when we know how long something takes and how much effort we need to put into it. We like when we know that our work will yield positive results and preferably the permanent kind. The 21/90 rule fits with everything we want when improving ourselves. But is the rule true?

Below we’ll look at what the 21/90 rule is and whether it’s the secret to habit-building and lifestyle changes.

What is the 21/90 rule?

The 21/90 rule is a theory that claims that if you do something for 21 days straight, it’ll become a habit, and once you’ve reached 90, it becomes a permanent lifestyle. Many have used or tried this theory as the framework for positive change.

Who came up with the theory?

In a self-help book called: “Psycho-Cybernetics, A New Way to Get More Living Out of Life.”, from 1960, a cosmetic surgeon named Dr. Maxwell Maltz first introduced the 21/90 theory. Since then, people have forgotten the book but his rule stuck.

Is the 21/90 rule true?

The 21/90 rule promises a simple way to build habits and change your lifestyle. But is it true? To determine if the rule is true, we’ll have a look at two things. Can you form a habit in 21 days, and can you create permanent lifestyle changes in 90 days?

Related: 5 common myths about habits

Can you form a habit in 21 days?

In 2009, a medical researcher named Phillippa Lally began a study to test how long it takes to form a habit.

The conclusion from the study was that it takes an average of 66 days to form a new habit. That’s 45 days more than the 21 claimed in the theory. In other words, it’s unlikely that you’ll be able to form a new habit in just 21 days which is what the 21/90 rule promises.

Related: What happens when you miss one day?

Can you create permanent changes to your lifestyle in 90 days?

The second part of the rule claims that you can make permanent changes to your lifestyle in 90 days. What we usually call lifestyle changes are actually just a change of habits.

We discovered that it takes an average of 66 days to form a habit, so changing your lifestyle in 90 days is very much possible. However, the 21/90 rule claims that you’re not just going to change your lifestyle, but that it will be permanent changes. This is where the issues with the second part of the theory start.

Your circumstances won’t be the same forever. You might get busy with a job, a family member passes away, or in other ways, experience stress. When your circumstances change, your habits are likely to experience change too. When this happens, you might regress back to bad habits you’ve worked to break in the past.

Remember, nothing in life is permanent, and your habits won’t be either. It doesn’t matter if you’ve done it for 90 days, 1 year, or 5 years. You have to make an effort to keep your good lifestyle alive, especially if it’s a difficult one.

Is the 21/90 rule the secret to self-improvement? THis infographic tells you why it isn't
The 21/90

Can the 21/90 rule be used for change?

We know that the 21/90 rule isn’t true. However, that doesn’t mean that it can’t be used to create positive change.

The more time you have to spend on achieving something, the harder it is to use willpower. If you know that you have to force yourself for 21 days, it seems far more manageable than 66. This way, you might be able to use your willpower in the often so difficult beginning. However, willpower is often unreliable, and better tools exist to successfully build good habits.

Once you reach 21 days, the habit might not be there yet, but it will be easier to do the behavior and slowly form it.

Related: Small wins and keystone habits

Sum up

The 21/90 rule claims you can build a habit in 21 days and permanently change your lifestyle in 90.

It takes an average of 66 days to form a new habit, 45 days more than the 21 claimed in this theory.

Life is unpredictable, and there is no such thing as a permanent lifestyle change. It can always change for the better or worse.

Despite the 21/90 rule being false, you can still use it for positive change. But remember, there are more effective tools for building habits.

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