Similar question came up on the Rocket forum... about changing oil for winter and should we worry about it??? Here was my extended answer... I agree with Dog too...
Short answer.... I really don't care.
If it is due because of mileage, I replace it. Otherwise it stays in the bike. I've never had an oil related issue storing the bike for the winter hibernation. I do use a premium motorcycle specific oil brand though. I have had the oil tested at the manufacturer's recommended oil change interval and it was still good to use... The riding climate in my home town is conducive to extending the oil change intervals. I typically run the oil in my bike to the recommended limit. Remember, a Rocket is no dirt bike so the oil remains generally free from outside contamination. You have to determine if the humidity is bad enough to warrant shorter oil drain intervals.
In the mine equipment field in one of the deepest base metal mines in the world I worked in for 37 years, we did extensive oil analysis testing. We found that with quality oil, we could extend oil life considerably by improving oil filtration using centrifical type filters (for engines to remove soot) and kidney loop filtration. Everthing on a loader or haul truck was extensively filtered improving component life dramatically. But this equipment didn't stop for any extended interval...
