A short 3 ft run from compressor to a water separator, M60 air filter, out via a short 3 ft run to a water separator and directly to my plasma cutter.
Air compressor is drained each and every day I run it, and on each new day I turn it on and run the drain to get rid of any moisture build up from sitting overnight (if any).
So filtration is at a minimum, but I try my best to keep it out as much as possible. Water separators are empty and filter looks to be damn new still.