Power tools have changed since a few decades ago. Even tools such as air compressors run mostly on battery power. Youtube channel This Old House in their video talks to an expert of several decades about what makes a good air compressor to use around the house.
An air compressor draws in the surrounding air, and then forces it under pressure into an air tank. Then, with the right equipment, the air is directed into a power tool.
Various compressor models have a valve that can control the amount of pressure going into whichever tool you have hooked up. These tools can take a lot, but be sure to read the specs on them so you know the maximum pressure limit.
Make sure the air filter is clean to prevent excessive dust build-up. You might have to repair the oil and belt sometimes, but only if the compressor model uses them. For humid environments, it’s important to drain the air out of the tank every day to prevent rust build-up and getting water into your power tools.
Before shopping for used air compressors, consider the size of the job to determine the size of the compressor you buy.