K&N calls for cleaning and oiling the filter every 50,000 miles. I have been running K&N filters on every car I have owned since 1996. Just follow the recommended mileage interval and you should be good.
Put an oiled AFE filter on my car today--took about 30 seconds--I didn't remove anything but the latches and filter--it slipped out within the space without having to remove anything else. It smoothed out daily driving--1-2 2-3 shifts and the butt dyno said it did some good. cockerdogs