Quote Originally Posted by Sausage
They should stay the same 24/7 unless you're breeding. As for unplugging it when it gets hot, you're gonna have to be sitting in front of the tank all day if you want to keep the temp steady. They get very hot very quickly and cool down quickly as well. I would rather invest in a heap rheostat like the one here. I use one and have had no problems. The hides also need to be identical(I use these ,they are tighter fitting than shown in the pic); just make sure they aren't the little half log hides, they aren't very secure. Branches are optional, but not necessary. And no, if your temps are fine with the UTH, a lamp is not necessary.
I saw one of those at the store I was at but didn't look at it much. So you're saying that the under tank heater will heat up the "hot" side of the tank to more than the recommended 90-94 degrees and that is why I need a thermostat so when it reaches that temperature it'll stay the same temperature instead of continuing to get hotter and hotter? Or can the thermostat completely replace the under tank heater? Sorry, I'm a little confused...this is my first reptile ever.

Also, how do I regulate the "cool" side of the tank? I understand I can use a heater to "heat up" the hot side but what do I use to ensure that the cool side really is between 80 and 84 degrees