A recipe for a habit

Ingredients: one small habit that takes ten minutes, one place, one fixed time of day, and thirty days.

Ingredients: a habit of $10$ min, a place, a fixed time, $30$ days.

Habit $h=10$ min, $d=30$ days.

Method: every day, at the same time and in the same place, do the habit for ten minutes and mark the day on a calendar. At the start never do more than ten minutes; a big start tires you out quickly.

Method: every day, same time, $10$ min; mark the day. At the start, never more than $10$ min.

Every day $k$: $\forall k\in \{1,\dots ,365\},h_k=10$

Result: after thirty days, ten times thirty is 300 minutes, which is five hours. After a year, ten times 365 is 3650 minutes, about 60.8 hours, nearly two and a half days.

After $30$ days: $10\times 30=300$ min, that is $5$ h. After a year: $10\times 365=3650$ min, that is about $60.8$ h or nearly $2.5$ days.

${\sum }_{k=1}^{30}{h}_k=300$ min, ${\sum }_{k=1}^{365}{h}_k=3650$ min, $3650/60\approx 60.8$ h

A tip: if you miss a day, do not do double the next day. A plan of two hours that lasts only three days gives two times three, six hours, far less than the 60.8 hours of the small habit.

Miss a day? Do not double. A plan of $2$ h that lasts $3$ days gives $2\times 3=6$ h, and $6<60.8$.

$2\times 3=6<60.8$ h