A basic, inexpensive analog scale ($10 and up), the kind that uses a needle pointer, suffices for most people, says Lara Sutton, RD, a nutritionist for Sports Club/LA in New York City. Look for one with a display you can clearly read while standing up and a platform on which your feet fit completely. If you really sweat the details, choose a digital scale that can chart 0.1-pound increments. That said, if you're serious about weight loss or you're an athlete, consider a costlier scale ($30 and up) that measures body-fat percentages, too. "This type of reading can help you see if you're building muscle and getting fitter," says Gregory Florez, a spokesperson for the America Council on Exercise who is based in Salt Lake City. While the body-fat calculation isn't 100 percent accurate, if you use the feature regularly, the readings will still help you to track your progress.