just a quick note if you are using a UTH and no thermostat make sure you have a nice think amount of bedding like Aspen or cypress. That tends to dissipate the heat enough to keep the animal safe(not a perfect way to do it but it works); However thermostat FTW! but if you already have a UTH just get a small lamp that will take care of the rest. Thats what i do.
and
I agree, i only really use my lamps in the winter as well and knowing the temps is Key.