as long as the filter is internally coated with sticky oil and not "dried up" with dirt and dust, it will do it's job. Blindly changing the filter every ride is, in my opinion, a waste of time and could possibly do more harm than good. It's ohh so easy to bump a bit of dirt into the air boot when changing a filter. Keep an eye on it and make sure it's well saturated with oil (just spraying the outer surface with oil doesn't cut it).
Coat the inside of the air boot between the filter and the carb with grease. Don't smear too much around the rear part of the carb, it could plug up one of the bleed passages. When changing the filter, stick your clean fingers back in the rear part of the boot, and feel for any grit. Also look at the grease and see if it looks dirty. The grease is dual purpose, to act as a warning that there is some problem allowing dirt in, and also to trap the dirt preventing damage (not perfect but it helps). Usually, the only evidence of dirt I find is in the very bottom, due to dirt falling in during the filter change, which I of coarse clean back out and re-grease as needed.
As far as drying, I use an old bath towel (or paper towels in a pinch) to absorb out most of the water. Next, I work the oil into a filter using a large ziplock bag. This chases any remaining water out, and it just goes to the bottom corner of the bag. With colored oil, it should be easy enough to see if this is working, or if there are unsaturated spots on the filter.
ditto on the sealed plastic bag disintegrating the filter.
cleaning filters is a necessary evil :p