# How long does it take to form a habit? Not 21 days

> The number 21 has been repeated for decades and comes from no study of habits. The study that actually measured it found a figure three times higher, with a very wide spread.

"Twenty-one days" is the most durable myth in self-improvement. It traces back
to an observation by the plastic surgeon Maxwell Maltz in the 1960s about how
long patients took to get used to a changed appearance. That was not a study
of habits, and it measured nothing we would now call automaticity.

## What the research found

In 2010, Phillippa Lally and colleagues published a study in which 96 people
each picked one new daily behaviour - drinking water with lunch, say, or a
short run before dinner - and reported every day for twelve weeks whether they
had done it and how automatic it felt.

Three points are worth keeping:

- **The median was 66 days.** That is how long a typical person took for the
  behaviour to reach automaticity.
- **The spread was enormous: 18 to 254 days.** There is no single number of
  days after which a habit is "done". It depends on the behaviour and the
  person.
- **Effortful behaviours such as exercise took longer** than eating and
  drinking ones.

## One missed day does not undo the progress

This is the most practical result of the study: missing a single day had no
material effect on habit formation. What mattered was repetition over time,
not an unbroken streak.

Worth knowing, because the streak counter that nearly every app shows teaches
the opposite. Once a streak breaks it is easy to conclude that everything
restarts from zero and drop the thing entirely. A run of days is good
motivation and a poor measure of progress. The share of days in the month is
better.

## What follows in practice

**Tie the habit to a specific cue.** "After I put the coffee cup down I do ten
squats" works better than "I will exercise more", because it takes the daily
decision out.

**Do not count down to a finish line.** With a spread reaching 254 days,
planning for 21 guarantees disappointment in week four, when the thing still
takes effort - which is normal, not failure.

**Start with one to three habits.** There is no hard data on the number, but
each extra habit is one more thing to remember on a day that is already full.

**Measure instead of remembering.** After a week, memory says "it went well".
Ticked-off days say exactly how well.

## A grid for the month

The [habit tracker](/en/tools/habit-tracker) is a plain grid: habits in rows,
days of the month in columns. It shows the streak and the month's score side
by side, precisely because the streak alone misleads. It needs no account,
saves in your browser, and prints or saves as a PDF in one click if you prefer
paper.

If you are still deciding which part of life to work on before picking a
habit, the [wheel of life](/en/tools/wheel-of-life) helps.

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Źródło: https://ordiarion.com/blog/how-long-to-form-a-habit