You have three ways to heat water. Gas, electric, or both. Two switches.
If the water in the tank is cold recovery time is likely an hour for electric, 40 minutes for gas, 20 for both. SWAG’s. Every unit is different.
So while in a campground with electricity we just leave the electric on. Flip the switch to gas on as well if anticipating lots of showers. Gas only while not on shore power.
If you turn everything off at bedtime it will save a little energy. Water would maybe be lukewarm in the am.