Good points on the different types of filters.
A re-useable K&N (or TRD & others) type filter should have the longest filter life of the filter types (K&N offer a 1,000,000 Mile warranty), however if they are not maintained they can cause considerable damage. The tacky oil traps the particles in the filter, after time it begins to clog and restricts airflow. At this time the filter should be cleaned and reoiled. If they are not kept oiled particles actually start to go through the filter and cause damage.
I have seen gouges from particles in the piping of an air intake due to someone not keeping their K&N oiled!.