I've had my fujita intake for over 25k miles and I have never washed or cleaned my filter.
How often are you supposed to wash/clean your filter?
It makes it hard to wash the filter and let it for a few days when you daily drive your car.

once a yr is a good rule of thumb

i usually do it in spring

As easy as stealing a candy from a kid, i'll do it everytime i change my oil. Take out and dust it, wash and let it dries. Also cleaning the tube and the box and the opening wide tube where the air comes in

Yeah. I used to do it every oil change, now its every month or two. Really it should be every 15k per the maintenance schedule.

reyoasian had a pretty good routine for doing it every year. and blitz_714 made a good point going as far as cleaning the intake tube as well. I would look up cleaning instructions for your specific part RE cleaning.