The 21/90 Rule: 3 Steps to Building Habits That Last

According to behavioral psychology, our brains tend to avoid anything uncomfortable or requiring significant effort. We procrastinate until later because they require big changes, like learning a new skill, going to bed early instead of staying up late, changing jobs, or facing our emotions...

Our brain has a region called the amygdala, which activates avoidance mechanisms when it senses danger (including anxiety and pressure) to keep us in our comfort zone. So, we tend to avoid it by putting things off.

The truth is: What you procrastinate on longest is often what will change your life profoundly.

The longer you put something off, the more important it likely is and the more positive change it could bring to your life. You're just afraid to face it.

One way that helped me get over my initial hesitation and start making changes was the 21/90 rule. It's a simple idea that helped me begin building habits and actions, starting small and gradually growing. This made change much less scary than I first thought.

So, what is the 21/90 rule? Let me walk you through how this works and how you can use it to create positive changes in your own life.

What Is the 21/90 Rule?

The 21/90 rule, actually, is a method for habit formation. It suggests a two-phase process: 21 days for initial habit development and 90 days for lifestyle integration.

What happens in the first 21 days?

During these 21 days, your brain is learning. How? Each time you repeat your chosen action, your brain remembers it better. Like cutting a path through thick grass: each time you walk the same way, it gets easier to see and follow.

Most of the time, these first weeks are the hardest. You will need to remind yourself to do your new habit. You might forget some days. There's no need to worry - I'm the same and so are many others. This is normal when you start something new.

Here are some good habits to start with:

• When you wake up, drink a glass of water.
• Before bed, read for ten minutes.
• After dinner, go for a short walk.
• Write down three things you're grateful for.

Keep in mind that 21 days is just a relative number. It may take longer for some habits to form than for others. But 21 days gives you a good first goal to aim for.

Why continue to 90 days?

You might wonder why you should do 90 days if 21 days will do the trick.

Here’s the thing: there is a massive difference between making something a habit and making it a part of who you are.

Your new habit will be normal and easy by day 90. You just do it, like how you don't think about brushing your teeth in the morning. These additional days help you practice your habit through different life situations: busy days, weekends, stressful times, travel, social events, etc. You will learn ways to keep up your habit even when things get tough.

Your sense of self starts to change, which may be the most important thing. You will no longer think, "I'm trying to exercise more", but "I am someone who exercises regularly". This change in identity is powerful and lasting.

3 Steps to Build Lasting Habits with the 21/90 Rule

We now know what the 21/90 rule is and how it works. Let's use it in real life. Here's exactly how to make this rule a part of your life by following these easy steps that you can start today.

Define your desired habit

The first thing you need to do is choose the right habit.  This may seem like a no-brainer, but a lot of people fail because the habits they choose are too vague or too ambitious.

Make your habit clear and easy to track. Instead of "exercise more," try "walk for 15 minutes after lunch". Instead of "eat healthier", choose "eat one serving of vegetables with dinner." Being clear about what success looks like helps your brain understand it better.

Also, think about what drives you deeper. Why does this habit matter to you? When the original excitement wears off, connecting your habit to your values makes you more motivated.

Create a plan for the first 21 days

The first 21 days are all about getting into a good habit pattern. To be successful, you can do:

Split up your habit into as many small steps as you can. For example, you can start with one minute if you want to meditate every day. Start with one paragraph if you want to write every day. That's why making your habit ridiculously small gets rid of the excuses of "not enough time" or "too tired".

Set aside a certain time to practice your new habit. Here’s one of my favorite habit hacks: Attaching your new habit to an existing routine creates a natural trigger.

To give you some examples:

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Develop a strategy for the next 90 days

Once you have a basic habit pattern, the next step is to make it stronger and deeper until it becomes a normal part of your life. “Developing a strategy” sounds fancy, but it's really just:

Plan for challenges you might face. Think about what might get in the way, like travel, busy work times, or social events, and make clear plans for how you'll stick to your habits when these things happen. Having a "minimum viable habit" version for days when things are hard helps you stay consistent.

Stay consistent with your habits. Find someone who can be your accountability partner, join a group of people with similar goals, or set up small prizes for reaching important goals. Time management tools, such as time blocking, can also protect your habit time from other tasks.

Track your habits to help you get going. You could use a simple wall calendar with Xs to mark your days, a habit-tracking app like Habitify that tracks your habits and shows your streaks clearly, or a habit journal to keep track of your progress. Seeing your consistency makes you more driven (it really works for me, try seeing yours!).

4 Challenges You Might Face (And How to Beat Them)

I believe that even people with the best intentions can face some hurdles when using the 21/90 rule. Everyone does. Let me share with you how to handle the most common ones:

When you start feeling bored

Between days 7 and 10, the excitement usually wears off. And this is totally normal. Whenever you feel like giving up, just remind yourself that this is a part of the process. If needed, make your habit smaller for a while. Focus not on how you feel while you're doing it, but on how you feel afterward. Don't forget that day 21 is coming up soon!

When you don't see results yet

I know, it's so frustrating when things don't change quickly. However, small steps that add up over time are what make the 21/90 rule work. If you want to stay inspired, keep track of your progress visually (as I said in the “3 steps” part).

Another good idea is to think about how you feel instead of what you see. For example, are you sleeping better? Do you feel more energetic? Is your mood getting better? Often, these changes happen inside before effects can be seen.

The truth is that most people give up just as the results begin to show. Understanding this time trap can help you keep going when you're losing patience.

When life gets crazy busy

There are weeks when everything seems to happen at the same time. When you're really busy, just make your habit as simple as possible. It only takes one minute to make a difference. The key is maintaining the pattern, not achieving perfection. The 21/90 rule works in real life because it is flexible. You won't have to start over once things calm down if you keep your habit alive in some small way.

When you skip days

When you miss a day (and you will!), simply start again the next day. As long as you don't let one missed day become two, it's okay. Getting back on track quickly is more important than achieving a perfect streak.

Final Thoughts

In essence, the 21/90 rule is simply 21 days to form a habit, and 90 days to make it part of your lifestyle.

I've used this method to build some good habits that have truly improved my life, like playing the piano, walking at 6 p.m., and writing every day. The thing I love most about the 21/90 rule is that it respects the way real change happens, which is slowly, with patience, and by doing small things over and over again.

Don't forget that the time will fly by. In ninety days, you might still be where you are now, or you might be a better version who has formed a new, good habit that sticks. So? Try not to overthink. Try beginning today. You will be what you repeatedly do.

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