If I'm in the trailer, I leave it going. However, if I'm going to be away for a weekend, I turn the water heater and pump off, then de-pressurize the system by opening the toilet valve. When I'm gone, I unplug and disconnect the battery, but that is usually because I am boondocking and would end up with those discharged due to parasitic losses.
I really wish RV makers would have some line of models where they didn't use cheap crimping on the plumbing and used home-grade electrical wiring. Perhaps 1-2 gauges larger, so a 1500 watt heater won't cause issues. I don't know what really is the best, but so far, I've seen far better ways to ensure PEX connections don't leak than the ear clips that most rings have.