I see many boats damaged by hasty, unprofessional, winterizing. Many boats are damaged, some even destroyed every year because the systems aren't given the attention they deserve. While everybody knows that the engine and freshwater system must be winterized, there are many small but critical jobs that should be done that tend to go unaddressed.
Was the engine intake sea strainer drained? Have biminis and dodgers been stored inside? Is the boat blocked properly for storage?
I could go on and on.
Look your boat is a major investment, are you going to take a chance of ruining everything to save (not if you do it wrong) a few dollars in winterizing your boat without a professional?