A large body of research has been developed in recent years to explain many aspects of willpower. Most of the researchers exploring self-control do so with an obvious goal in mind: How can willpower be strengthened? If willpower is truly a limited resource, as the research suggests, what can be done to make it stay strong?Avoiding temptation (诱惑) is an effective method for maintaining self-control, which is called the “out of sight, out of mind” principle. One recent study, for instance, found office workers less attracted to candy in the desk drawer than that on top of their desks, in plain sight.The research suggesting that we possess a limited reservoir of self-control raises a troubling question. When we face too many temptations, are we to fail? Not necessarily. Researchers don’t believe that one’s willpower is ever completely exhausted. Rather, people appear to hold some willpower in reserve, saved for future demands. The right motivation allows us to tap into those reserves, allowing us to carry on even when our self-control strength has been run down. High motivation might help overcome weakened willpower-at least to a point.Willpower may also be made less vulnerable(脆弱)to being exhausted in the first place. Researchers who study self-control often describe it as being like a muscle that gets tired with heavy use. But there is another aspect to the muscle comparison, they say. While muscles become exhausted by exercise in the short term, they are strengthened by regular exercise in the long term. Similarly, regular practices of self-control may improve willpower strength.The evidence from willpower-exhaustion studies also suggests that making a list of resolutions on New Year’s Eve is the worst possible approach. Being exhausted in one area can reduce willpower in other areas, so it makes more sense to focus on a single goal at a time. In other words, don’t try to quit smoking, adopt a healthy diet and start a new exercise plan at the same time. Taking goals one by one is a better approach. Once a good habit is in place, Baumeister says, you’ll no longer need to draw on your willpower to maintain the behavior. Eventually healthy habits will become routine, and won’t require making decisions at all.