Stud finder apps use a magnetometer in the phone to detect metal. Many handymen prefer a density-reading stud finder, especially for more valuable projects like mounting a 65-inch TV to your wall.

Master this tool and technique, and you can rest assured that whatever you mount to the wall—mirror, television, or shelves—will stay in place.

Knocking, using magnets, and flashlights are a few ways to help you locate a stud without a stud finder.