Leave it on or turn it off?

The case for "leaving it on":

Claim 1: the temperature of the components stabilize, providing a consistent sound.

Claim 2: the sound is better, because the temperature is stabilized at the design temperature, which the unit presuma bly ran at while being voiced by the designer.

Claim 3: reliability is better, due to absence of thermal cycling and resultant mechanical stresses on the components and circuit interconnections.

Claim 4: reliability is better, due to absence of large inrush currents at power-on.

There's also a good case to be made for leaving power amps turned off (but that's not your question). Suffice it to say I've considered both sides of the issue and leave my space heater (Aragon 8008 BB) turned off when not in use.

Glen, Living in california, we turn it all off when not using. "Kill A Watt" is our moto out here!
We have a CA300. When it was in the 2 channel setup, we would just let it warm up for a while before listening. Now that it's in the HT, we just turn it on right when we sit down to watch a movie. (hey, Steve!)

Hi Glen; 1439 makes good points, but another possibility, and the one I use, is to turn the amp on in the morning to warm up, and off after listening at night. I have a McCormack DNA-2DX Rev. A (also 300 wpc, like your Classe'). It runs fairly hot while playing, but drops into standby mode after no signal for 10 minutes. Still, I prefer to be 50% environmentally friendly, and so turn it off at night. Cheers. Craig