habit (n)

I always buy the same brand of toothpaste out of (= because of) habit.
I'm trying not to get into (= start) the habit of always having biscuits with my coffee.
I used to swim twice a week, but I seem to have got out of (= ended) the habit recently.
Biting nails can become an unconscious habit.
Breaking a bad habit often requires conscious effort.
Starting the day with coffee became a morning habit.
Regular exercise is a healthy habit to adopt.