Look for a stud finder with a scanning depth of 1½ inches. Some stud finders have an auto recalibration feature, which is useful when you inadvertently begin your scan over a stud and then move the finder away from it. If you’re planning to nail or drill deep into your studs — 3 inches or more — it’s worth investing in a stud sensor that can detect live wires embedded in the studs. Most stud finders these days are made from lightweight but rugged plastic. Some have special non-marring pads to prevent any damage to the wall.