A major misconception around habits is that willpower is the source of sustained change. It is easy to see others who have healthy, effective, rock-solid habits and assume they have unnatural reserves of self-discipline. But research has shown that willpower is like a muscle; it gets tired when exerted for extended periods of time. So, building new habits is less about grit and more about strategy. You’ll increase your chances of success by understanding how to break a habit into pieces—and then making a plan.