Psychologists say you should only make New Year’s resolutions if you really want to change, says Business Insider. Self-motivation is easy to find if you’re doing something for yourself; if you can’t get motivated, maybe the goal of the resolution isn’t really that important. If you can keep a promise to yourself for a full month, you’ll be well on the way to forming a new habit, and habits — good and bad — are hard to break. And it’s easier to succeed in your resolutions if you can replace an old, unwanted or counterproductive habit with a new, more positive one.