Just to add to this discussion ...years ago we were in an RV park next to owners of a fishing lodge in Ontario. It was remote and only accessible by seaplane.
They had a pair of Kubota generators like we use in our coaches. For the entire six month season the generators ran 24/7. Instead of a crankcase like we have they plumbed their oil to the generators from a 55 gallon drum. So for 180 days and about 4300 hours they never changed oil, just ran them using the 55 gallon drum of oil as a sump. At the end of the season it was replaced with a new drum of oil.
The engines had 28,000 hours on them and were still going strong. The only thing they did special was every week or so they would load the generators with about 14,000 watt loads (two huge electric heaters) just to make them work and burn off any carbon that accumulated from light loads. Their opinion was lightly loading the generators was detrimental.