You've probably heard that it takes 21 days to form a habit. Or was it 66 days? The truth is, the timeline doesn't matter nearly as much as the strategy. When it comes to building a daily brain game habit, most people approach it all wrong – and that's why they fail.

Here's what actually works, backed by behavioral science.

Start Absurdly Small

The biggest mistake people make is starting too ambitiously. "I'll do a 30-minute brain training session every morning!" sounds great until day three rolls around.

Instead, start with just one puzzle. Not a full session – one single puzzle.

Research from Stanford behavior scientist BJ Fogg shows that tiny habits are far more likely to stick than ambitious ones[^1]. Why? Because you're not relying on motivation, which fluctuates. You're building a neural pathway through repetition.

A study published in the European Journal of Social Psychology found that it takes an average of 66 days to form a habit, but the range varied from 18 to 254 days depending on complexity[^2]. Starting small shortens your path to automaticity.

Anchor to Something You Already Do

Don't just say "I'll play brain games daily." That's too vague to become automatic.

Instead, link your new habit to an existing one:

After my morning coffee → one crossword clue
While waiting for my computer to start → one Wordle guess
During my lunch break → one quick puzzle round

This technique, called "habit stacking," was popularized by James Clear in Atomic Habits, but the concept is rooted in decades of psychology research on implementation intentions[^3].

When you pair a new behavior with an established routine, you're leveraging existing neural pathways rather than building from scratch.

Make It Easier Than Not Doing It

Friction is the silent habit killer. Every extra step between you and your brain game is another chance to skip it.

Reduce friction by:

Keeping the brain game app on your phone's home screen
Bookmarking your favorite puzzle site in your browser
Setting up notifications (but only if they help, not annoy)

A University College London study found that habit formation is strongly influenced by environmental factors[^2]. The easier you make the desired behavior, the more likely it becomes automatic.

Put another way: make doing the habit easier than not doing it.

Don't Rely on Streaks (At First)

Popular apps love to gamify streaks – "Don't break your 47-day streak!" But here's the problem: when you inevitably miss a day, that broken streak can kill your motivation entirely.

Better approach: Focus on frequency over perfection.

Research on habit formation shows that missing one day doesn't significantly harm habit development, as long as you get back on track quickly[^2]. The key is consistency over time, not an unbroken chain.

Think of it like this: doing your brain game 6 days a week for a year (312 days) is vastly better than doing it for 50 days straight and then quitting when you break the streak.

Combine It With Something You Enjoy

Your brain releases dopamine in response to rewarding experiences. You can hijack this system to make your habit more appealing.

Try pairing your brain game with:

Your favorite beverage (morning coffee + crossword)
Relaxing music in the background
A comfortable spot you love

Over time, your brain will start associating the puzzle with the pleasure of the accompanying activity, creating a positive feedback loop.

The Two-Day Rule

Here's one of the most powerful habit-building principles: never miss twice in a row.

Missing one day is life. Missing two days is the start of a new (bad) habit.

When you miss a day – and you will – your only job is to make sure you do it the next day, no matter what. Even if it's just one puzzle right before bed.

This rule, mentioned by productivity researcher Nir Eyal, acknowledges that perfection is impossible while preventing the spiral that kills most habit attempts¹.

Track Progress, Not Perfection

Instead of obsessing over an unbroken streak, track your habit in a more forgiving way:

How many days this week? (Aim for 5+)
How many weeks in a row have I done at least 5 days? (Track your consistency over time)

This reframes your habit from a fragile chain that can break into a robust pattern that can withstand occasional misses.

The First 10 Days Are Critical

Research shows the first two weeks are when most people abandon new habits². This is when you need the most support structure:

Use reminders and alarms
Tell someone about your goal
Make it so easy you can't say no

After about 10 days, it starts requiring less conscious effort. After 66 days on average, it becomes genuinely automatic³.

Your Action Plan

Starting tomorrow, commit to this simple protocol:

Choose your trigger: "After [existing habit], I will do one puzzle"
Remove friction: Put the puzzle where you'll see it at the trigger time
Start tiny: Just one puzzle, every day
Never miss twice: Life happens, but get back on track immediately
Track weekly: Count days per week, not total streak

Remember: the goal isn't to do brain games perfectly. The goal is to build a habit so automatic that not doing it feels wrong.

That's when you know it's truly stuck.

References

Eyal, N. (2019). Indistractable: How to Control Your Attention and Choose Your Life. BenBella Books.
Fogg, BJ. Tiny Habits: The Small Changes That Change Everything. Houghton Mifflin Harcourt, 2019.
Lally, P., van Jaarsveld, C. H. M., Potts, H. W. W., & Wardle, J. (2010). How are habits formed: Modelling habit formation in the real world. European Journal of Social Psychology, 40(6), 998-1009.