I have both 1000 and 2000 Honda Generators. I purchased the 1000 3 years ago and my bride won the 2000 a year ago. I believe in using Mobile 1 synthetic in all my engines. One oil change a year for the boat, RV, Corvette, Mgb, lawn mower Etc.
I use the Honda 1000 on the Sea Ray boat mostly, and change the oil every 20 to 25 hours. A weekend trip uses maybe 2 gal of gas. The Onan onboard would use about 12 to 14 gal. When the Onan died for a simple reason, it was removed ( and sold ) saving many hundreds of pounds and the Honda is simply placed on the swim platform when needed.
Boon-docking a weekend in the RV I use the 2000, run the AC, TVs Ect, usually requiring less than 4 gal as the AC runs longer than on the boat. Onan uses about .5 gal per hour. I still run the on-board Onan each month and change the oil yearly to prevent early demise.
Bottom line - OIL is cheap, easy to change in portable gensets, change it often.
Cheers All.