Well, yes I do. When I recently took a bike on vacation that rode through heavy rains while on the car rack, I immediately pulled the seatpost and dumped maybe 1/4' cup of water out. I put a coating of grease on the seat post when I re-installed it to seal and prevent removal issues later. I know what the seat post measurement is, so setting my ride height is no problem. If you've ridden in the rain it is a cheap and quick bit of maintenance that you should do.