Only you can decide if it's better for your situation, but there is nothing wrong with leaving it on as long as your RV is reasonably level while doing so. We do have our rig plugged in all the time stored at home in our side yard, we usually have fridge running during the camping season but when there is a few weeks of gap between trips we will power off the unit. I've noticed about a $12-$15 increase in our monthly electric bill which wouldn't have any affect on my decision to keep our fridge on or off while we weren't camping.