I have seen one that was reported to have over 4400 hours on it, with only regular scheduled oil changes and a valve adjustment every 1000 hours. I wish I could find the thread, I would post it here.
I work for a large water wholesaler and we have at least 25 Honda EU2000i generators. In my department alone we have 12 and each truck carries one to provide emergency power to water delivery facilities during power outages, scheduled maintenance, and emergencies. We have several six gallon tanks and we have been known to run the generators continuously for several days at a time. Fleet maintenance does not track the hours on the small equipment, and most of the guys don't know or care about the service requirements. Seven of the generators are from 2001, and are probably on their second oil change in that 10 year span, and that would be the bulk 15w40 the diesel trucks are serviced with. They still start on the first or second pull, and do not smoke. The other 5 are new this year and still on the initial fill of the same oil.
Basically just run good oil, change it every fifty hours, and check the spark plug once a year. It will last you a long time. If we can't kill them with our abuse, you won't with your care.