In my old tent trailer I had to light the pilot light on the HW heater. Once heated the pilot light seemed to keep it up to temp without the burner coming on. I didn't worry about it.
In my current trailer I don't have the electrical option and the heater is electronic. We turn it off every night because I don't like the noise it makes when it comes on in the early morning hours. The tank sits right next to our bed.
Even when it is cold out, it doesn't take all that long before you have hot water. You don't have to wait for it to go off before you can shower or wash dishes. I try to conserve propane and usually turn it off.