112RD50 Operational Question

Since there is no standby, should I switch power off if I will be using the amp within 5 minutes, or 2 hours, or just to unplug and switch gear? Is there a warm up period? I have always used standby on my Marshall for these purposes, even before power off.

If it was 5 minutes, I would leave it ON and turn the volume down.
If it was two hours, I would turn it off for 1 hour 55 minutes and let it warm up for a few minutes before playing through it again.
I tend to leave things on all the time (like my computer), but tube electronics use electricity and generate heat at a higher level so I tend to turn them off unless I am getting back to them in under an hour.
Your mileage may vary.