I always flip 'em on and leave 'em on for 10-15 minutes. I only used the standby switch during breaks back in the day when we played as weekend warriors. When the tubes were hot they just sounded better. The old Fender Super got hotter and better as the night went on................ I also cranked it to 8 or 9 on the volume and used the guitar volume to adjust the level to where I wanted it. It seemed to be more touch sensitive that way.