If u don't oil the outer filter u mite want to consider changing ur filters every run, here in Cali when it gets dusty an oiled putter filter changes the tune so fast so I typically oil the inner filter then I actually take the outer filter and oil just the inner part with my finger leaving the outer part of the filter dry to not grab dirt. I still change my filters after each run tho it's not worth a 300$ engine to b lazy with a dollar filter.