How often does your water heater run? Been laying here for quite along time trying to fall asleep and it fires up about every 5 minutes, runs for about a minute and shuts off. That normal?

I believe its because its set to maintain a set temperature. I usually just shut mine off if no one is using the shower, propane lasts longer.

I would check the thermostat, cheep and easy to replace....

Something doesn't sound right, unless it's sub-arctic temps outside.
Mine will usually run once every couple hours at most during the day when it's anywhere from 65-85 outside (obviously when nobody is using the hot water). It's never cycled that often even when we've been in the snow.