Sooner or later, every builder will need to drill a hole into something. Whether it's a wooden frame, a sheet of metal or a brick wall, eventually the builder must use a tool designed to bore holes into building materials. That's where the power drill comes in.
Power drills come in two major varieties: those with power cords and those with batteries. Cordless drills are easier to work with in most situations, but the battery charge won't last forever. In either case, a power drill works by spinning a drill bit rapidly. The drill bit does the actual boring. It's held in place by the power drill's chuck, which is like a vise. Power drill chucks come in different sizes -- the size of the chuck determines the size of drill bits the drill can use.
Drill bits wear down over time, so it's important to inspect them before any job. If you work on a lot of construction jobs, you may need to replace your drill bits on a regular basis. For the average user, a set of drill bits may outlast the life of his or her power drill.