bigger UTH

i have a UTH that i first got when my bp was just a little guy. is it a must to buy a bigger one to put under his hot side hide.

I normally will use a UTH that covers about 1/3 to 1/2 of the floor of the enclosure, since I don't use lamps. But, if you are maintaining proper temps and humidity with your current set-up, I don't see why another one would be all that necessary...

well i have the UTH on a thermostat along with a red heat bulb. i know bulbs are not the best but its what i use. The thermostat is under his hot hide under the substrate. and it turns off and on all day. i have the therm set at 91. so im assuming as long as it keeps turning on and off then he is not having a problem keeping warm