I never leave anything turned on if I'm not in the operating or workbench area. Makes no sense to do that, it's not safe, and it's a waste of electricity which costs money. Plus, if there's a short or breakdown in a rig or power strip, you can burn everything, including your structure, into a heap of ashes. I'm sure the insurance investigator would be very consoling if they discover the amplifier was the source of the fire and then you tell them your amplifier hadn't been powered off for the last 2 years and never had a problem before. Equipment come with ON/OFF power switches for a reason.