My business generator auto-runs (exercises) for 15 minutes every week.
My gasoline generators I run once a month.
My 2kw Honda generator is also my camping generator so I only need to test run during the off season. We have lived off our generator in deer camp for over a week in a camping trailer. The main draw was the propane furnace fan (battery charge simultaneously). We found we could get by on a gallon of gas a day.
Power outage at home I can get by with less as I am only running a freezer and fridge, microwave, coffee pot and LED lighting (simultaneously battery charge on low draws) for short periods. We had grandkids over for power outages because we could run TV off Dish.