Hammer drills are a type of drill that's used to drill into harder substances like brick, stone, and concrete. These drills are often used by construction workers and if you've ever walked by a construction site, you've probably seen one. Since they're a professional grade tool, it's hard to justify the expense if you're not using it on a regular basis. You would generally only buy a hammer drill if you're a serious DIY'er or you're taking on a large home project that requires one. However, you can easily and affordably rent one at the local hardware store in most towns so that's something I would look into before purchasing.
Since there are different types of hammer drills, you can use them for different things. Here are some examples for each:
Being the larger hammer drill, these are used for heavy duty projects.
These are the smaller battery operated handheld drills that every homeowner should have. These are best used for...
There are several types of hammer drills including dedicated hammer drills and normal drills with the hammer option.
A dedicated hammer drill, also called a rotary hammer, is the one that's usually only used by contractors. They're heavy duty drills that often have an extra handle on the side for drilling through thick concrete and stone. You may have seen your cable guy use this if he had drill through brick to run cable into your house.
Corded hammer drills are best when you have a bunch of holes to drill or you just need a drill that can sustain an even level of power without switching batteries. Keep in mind that you'll need a power source nearby and they tend to have a higher RPM.
Over the last few years cordless drill have come a long way. Many of them have power levels that are close to that of corded drills. If you don't need to drill many holes or don't have a power source nearby, then a cordless hammer drill is a great choice. If you're a DIY'er or need a powerful drill for around the house, this is the way to go.
Not everyone needs a hammer drill. Since they're used for drilling holes in hard materials and not for drilling in screws, if you're not drilling holes in cement or brick, you don't need it. However, if you have any DIY projects or handy man projects around the house, you should have an 18v cordless drill. These can be used to drill holes in wood and almost any other material that isn't as hard as stone.