I have a 30 amp plugs (yes plural) at my house. RV stays plugged up 24/7 ready to roll at a moment's notice. Depending on your on board charger will depend on how well your batteries stay maintained. If you have an old 2 or 3 stage it might not be a good idea to leave it plugged up, if you have one of the newer ones you should be fine. I also use my EMS/Surge protector even when plugging in at home.
In the hotter months we set the A/C on 84° to keep it tolerable inside, turn the fridge on a day before we are ready to go. We try to camp at least once a month year round, and drive the camper somewhere ever couple of weeks just to keep the chassis exercised.