Habit formation is the process by which new behaviors become automatic. If you instinctively reach for a cigarette the moment you wake up in the morning, you have a habit. By the same token, if you feel inclined to lace up your running shoes and hit the streets as soon as you get home, you've acquired a habit. Old habits are hard to break and new habits are hard to form. That's because the behavioral patterns we repeat most often are literally etched into our neural pathways. The good news is that, through repetition, it's possible to form—and maintain—new habits.