Whether you're taking on a new difficult project or you have a few simple around the house projects, a good hammer drill can come in handy. When you have a substance like stone, concrete, or brick to chip up or cut through, a quality hammer drill should be your go-to and its one of the main tools used for this type of project. It helps you quickly get the job done in an efficient way with minimal effort and in the shortest amount of time.
There are two main types of hammer drills you'll find. The first is a dedicated hammer drill. These are usually corded and higher power. They're the best ones for chipping up tile floors, breaking up bricks, drilling larger/deeper holes, and breaking up stone. These are sometimes called rotary hammers and because they're corded, they don't quit. They also have a "hammer only" option which is ideal for chipping up tile or pounding through stone/concrete.
You'll generally find these in use on construction sites where they're used to bore holes for inserting rebar or drilling holes in block walls for wires and pipes. These can accommodate larger drill bits with more power to drill bigger holes. You may also see your cable guy using one when they drill holes through walls to run wiring from the outside of the house to the inside.
Then there are cordless drills with a hammer function. These are battery powered and lower power as far as the hammering function goes. They're better for the simple around the house type projects. Most commonly, they're used for drilling holes in softer materials, smaller holes in harder materials and screwing in screws.
Dedicated hammer drills aren't good for drilling in screws and in fact aren't built for this. They're strictly built to be a work horse. The handheld drills with hammer function are ideal for around the house projects because they can both drill holes and screw in screws.
What makes a hammer drill a hammer drill is that they have an internal hammer that repeatedly pounds the back of the drill bit. This helps to add more force behind the bit and drive it deeper into the material.
For most people, the cordless drill with a hammer function is the best way to go. You can easily get through most tough materials like metal, wood, and plastics without much effort. You can then press a button to switch out of the hammer setting and start putting screws in. Just make sure you switch your bit to the proper one for the medium you're drilling into. Not doing that can damage or quickly wear your bits out.