I like to have new oil in for winterization to get the acids and contaminants out of the crankcase for storage. New oil should protect for corrosion during layup. This means that oil that is used for one startup sits in the crankcase and deteriorates for 5 months. Which is most important getting the oil out after the season, or having fresh oil for the start of the season? I currently do oil change at layup, but would like to have fresh oil in the spring.