One of the most important things to know about air compressors is how big or small they should go. The best way to start answering this question is to examine the tools you want to use. Are you interested in an air compressor for tools that use short bursts of air such as a nail gun? Or are you in need of continuous air for tools like drills and sandblasters? If you need continuous air, you should get something with more power. Short blasts of air don't require as much power, so you can safely go smaller for impact tools and nail guns. Take a good look at your plans for the air tools before deciding which size compressor to buy.