I do too have one mounted !! the main reason to use a reusable filter is the fact that upon oil change the inner filter gets to be washed in varsol over a fine cloth and CHECKED for metal then if some fine metal particles are found, by running a magnet over you can determine if some preventive maintenance is required ( AKA big big saving) before all goes to pot even with fresh oil . when I flew radial engines airplanes, every 50 hrs we pulled the filters screens and checked the filters that way to ensure long life for the engine, a cheap way to get piece of mind believe me!!! now with a paper filter you throw it away when you change oil but you are none the wiser!!