While some experts advise focusing on one habit project at a time to avoid draining willpower, others note that people who work on one positive habit often find it easier to improve in other areas; for instance, people who stick to a program of exercise also show better health- and work-related behaviors. Maybe that’s one reason so many major religions have periods of ritualized self-denial, like Lent, Ramadan, and Yom Kippur. Self-command breeds self-command, and change fosters change. The reverse is true, too: undesirable habits often cluster together and reinforce each other.
