Some people suggest that it can take anywhere between 21 and 30 days to form a habit, but is there any science behind these timelines?

Goals, Habits, Science and Research, Tips and Tricks
Some people suggest that it can take anywhere between 21 and 30 days to form a habit, but is there any science behind these timelines?
Exercise, Goals, Motivation, Resolution, Tips and Tricks
Check out these quick tips to help you stay motivated to exercise.