(Pre)amp on or off?

[Clueless]

Turn the (pre) amp off when not in use or leave it on at all times?

This question is not new, I now. But the opinions seem to differ. For example, there's the argument that the component's age decreases proportionally with their average temperature. But on the other hand, some argue that the warmup/cool down cycle does more harm than just leaving the device on.
I think primarily about class A pre/amps, but not exclusively. Maybe each type behaves differently?

What say you?

[GRollins]

I turn tube gear off when not in use. All tube gear--even preamps and such.
Solid state amps I turn off, but preamps and crossovers and the like will do no harm if left on, and they use very little power. If you're running things so hot that they're breaking down, you need to spend a little more time on the cooling part of the design phase. I can't remember ever running across a low level circuit that died because of a transistor failure, unless it was due to a lightning strike, in which case all bets are off. The only failure you're likely to see is caps, and the small ones will last for ten or twenty years, easily.
Ten or twenty years?
By then you're going to have moved on to a new design, anyway, right?

Grey