If your amp has a standby switch I would use it; if not based on your info I would leave the system on.I would power down when you know you won't be listening until the next day.
How should you treat your tubes?
I recently swithed from SS to all-tube amp and preamp. I usually listen to my stereo in long stretches throughout the day and evening but there are also intervals when I am not listening. My question: Do I turn off the amp and preamp during those intervals which may last as long as an hour or two hours? Or do I leave my system on during the day and evening and turn it off at night? Thanks for any suggestions. JNorth1178