When you take a step back and see all the sleds...older sleds sitting around in the rain and sun all summer and then get pressed into action when the snow flies, and figure THOSE SLEDS have not had a darn thing done to them one has to wonder about the need to do all this "winterizing, summerizing" at all. Still it makes folks feel better and I can't think of a reason not to do it.
I think that the environment that you store your toys in, has a great deal to do with how it will come thru the off season. Damp wet environments might bring on a greater need to protect than say something stored in a barn or covered trailer that is vented.
One thing for sure, is that running it from time to time might be a greater protection than anything else you can do to prolong the life of any engine that requires fuel.
Remember some folks polish their shoes and others like me, just use the back of a pantleg once in awhile and then just use them. So far so good!