Fifteen to twenty years seems like a “proven result” to me; why change what seems to be working.
I start my generator at least once a month and let it run for about 15 min (generally I put at least some load on it 20% - 75%). In the winter I may start it twice a month or more depending on prevailing temperatures). I generally only keep a minimal amount of gas in it and freshen it often. Every 6 mo. or so I will drain it, put the old into a can with 6 gal of new, then pour a some back into the gen.
I have a second gen at the cottage. This one sits all winter without being started. So I run that one dry in the fall when we close up for the winter. Other than that, I do the same thing with that one.