Battery drain. If you wish to limit generator run time, you'll need batteries and they will drain over time even when not being used. You could bring the battery home and keep it on battery tender. My fridge runs on gas but needs a spark from the battery to fire it up. Same with furnance. I stay mostly in state parks with limited genny run times (about 2 hours) which isn't enough to charge battery fully so I don't know how long it takes a genny to charge batteries fully. Also, water and sewer. You didn't ask about those but sewer is the reason I need to move the TT every once in a while.