For me any temp that would mess up the attenuation of the style I'm brewing. Other than that I can't see much attenuation above 160*
Pretty much my thought too I was just curious if he had any specifics on it. The way mine works is if I have my controller set to 152 it will go to 151 before it comes on and shut off at 153. I take that into consideration when I pick a mash temp.