Leave tube amps always on?

Nobody leaves tube amps on all the time turn on 1 hour before listing is enough.

@1extreme 

@larryi 

Thx, super helpful explanation and information. A very knowledgeable forum. 

BS, it absolutely does not cost you more energy to turn your tube amps on an off relative to leaving them on all the time. Tube life is shortened but not as dramatically as you would think. I do know some people who keep them on because they hate waiting for them to warm up. They are also filthy rich and could care less about tube life. Some tube units like my ARC phono amp have low power standby modes. I do leave that on continuously. I have a class AB SS amp in the workshop that I leave on all the time but the JC 1's in the main system are turned off.
Turning the tubes on and off stresses the filament due to expansion and contraction of the metal with the extreme changes in temperature. Same for transistors although the temperature changes are not as extreme. 

Tubes consume more power if turned on and off regularly so you should leave them on all the time? Clearly a flawed logic from the LTA owner 

Two years ago I asked Kevin Deal, Upscale Audio at the RMAF show (Denver) should you leave an integrated amp on 24/7 or only when needed.  His expression and definitive answer was "Only on when you use it!"All my integrated amp's tubes still sound good today.  I just occasionally clean their pins.  :-)