I would never, ever, ever advise powering down between sets. Absolutely no reason too this and you risk a whole shit ton of problems. Mainly your FOH/monitors or personal monitors being shredded by you power cycling and them not being muted by the sound guy, or if your band runs them yourself. Also, same thing with turning the unit on. You have to make sure you're cab is muted, the FOH etc etc is muted when you power back on. Lots of guys unmute when the band walks back on stage. You'll scare the hell out of everyone with a 100dB pop.
In short, never power anything off that you couldn't live with it not turning back on as well. Most problems with gear happen on power cycling.
Practical answer: engage tuner mute. I finish the set, I hit tuner on my midi pedal (this mutes input) before I even walk towards the side of the stage - do this BEFORE you put your guitar in your stand. As I've had plenty of times taking the guitar off and I catch the jack and get a THUMP thru the rig, or when putting it into the coffin case the vol knob gets turned and you have noise screaming out at stage volume, or again jack gets hit or bumped, shit always happens live. Don't rely on sound guys, rely on yourself - they will always fuck you eventually.