Stupid question of the day: Should I leave Amp on?

I ultimately had to decide that burning the tubes for hundreds of hours when I am not listening is too high a price to pay for the small, but precious, number of enhanced listening hours. Have left on solid state equipment, without the same misgivings, since there is not the more obvious aging seen with tubes, and lack of a power switch seems to be a hint from the manufacturers when it doesn't worry them.