I change it on some bikes, and even fill the crankcase (where I can) for real long term storage, but it seems to work just as well to use a good oil (full synthetic is best because it clings well) and get the oil good and hot by riding before you park for storage. This drives the moisture out. You can't do anything else about the moisture, because you can't completely fill the crankcase. Today's top quality oils have buffers to prevent acid formation, so the used oil is not as corrosive as in times gone by. The Spyder is dry sump, so oil doesn't sit around the engine components, allowing corrosion to form at the oil surface as it can do with conventional oiling systems. I do get in long rides for most of the winter, but in a harsh winter my motorcycles are idle for 6-8 weeks sometimes. I have never had problems...even in engines that I tore down to inspect. The ideal thing to do would be to change oil when entering storage, to get rid of acid-forming contaminants, then change again before you ride in the Spring, to get rid of the moisture and oxidized oil. With 26 motorcycles, that is a gargantuan task (and it isn't very green). My evil ways have not hurt my machines, though.
