Always store tools in a dry, climate-controlled environment. Moist and dirty environments can cause hand tools to rust and dull, and storing power tools in damp areas can degrade electrical components and cause parts to corrode over time. While fitting power tools back into their cases can be a pain, the case will go a long way towards protecting its tool from the environment.
It might seem like overkill at first, but be sure that each of your power tools gets cleaned every time you finish using it. Cleaning methods will vary from tool to tool, but most of the time everyday cleaning can be as simple as wiping dirt and dust from the casing. Something as simple as a good wipe down will keep particles from building up and getting into your tool’s internal mechanisms. Tighter areas like filters can be kept dust free with a few blasts from a can of compressed air.
Remember to regularly inspect your tools
If you are in the habit of using a power tool every day, it can be easy to fail to notice when that tool’s performance gradually drops over time. That’s why it is important to at least semi-regularly take a moment and inspect your most-used tools, paying close attention to signs of wear and performance issues. Run a few basic operations with a tool, paying close attention to warning signs like weaker than normal power levels, any sort of burning smell, and strange buzzes and noises coming from inside the tool. Any of these is a pretty strong indicator that there’s something off with your tool and it may require some extra attention.