Turn off or leave on?

My solid state monoblocks draw 420 watts each in standby. Just part of the cost of having large class a Amps. Even so it takes a hour for them to sound decent. The preamplifier is one all the time as well. I never bother turning off to standby. The front end is all tube so it gets turned on and off when I go down to listen. Many times I turn it on then make and eat supper then go back down and everything is super then. On my second system it is a tube system except the Krell cd player it gets left on. Takes it at least a week if shut off before it sounds it's best. Bedroom system is tube based except the cd player which is left on. The integrated amplifier is a tube one and I have it on a timer. I turn the timer on for a half hour and it shuts down after I am asleep. 

makes me wonder if any of you got electronics training ...

1. there is no harmful effect to non-tube equipment to turn it on or off (unless somebody decides to sit and push the power button on/off for 2-3 hours ) thus, to save electricity turn it off.

2. Tube stuff...here comes the pickle...the tubes normally go weak slow losing cathode emission. Emission is the process when electrons are flying out of the heated cathode... now here is the fun part...at turn on the heating element in the tube starts to heat the cathode and it takes 2-5 minutes to get to the correct temperature .during this period electrons slowly start flying off the cathode to anode under voltage potential on anode and greed(s) . while the cathode is not hot enough electrons are not flying out freely but are kinda "ripped" from it. and it creates micro-cracks and the slow destruction of a cathode .that is how over the years tubes go bad most of the time. Now ,if the heater in tubes is always ON and the cathode is always hot , tubes may last 2-3 times longer. in the old days of picture tube TVs, there were enthusiasts who installed a circuit to apply a permanent supply to the heater of a picture tube extending its life. Now, to turn off tube gear or not is your choice ...no advice from me at this point. Good luck my HI-FI enthusiasts

It seems to me that many tube equipment manufacturers recommend that equipment not be left on while "unattended", due to the (small) risk of fire hazard should a tube fail.  Not sure how well I would sleep at night knowing my tube mono blocks could kills me in a house fire.  🤣

Its my understanding that the expansion with heat followed by the contraction from cooling off causes metal fatigue in the solder forming cracks.    Leaving class A amps on 24/7 is expensive, hard on the electric bill and a fire hazard.   That's a good enough reason to buy class D amps.

According to the rebuilder of my solid state (integrated) amp, it should be left on all the time for longest life of the electronics. On their newer models they moved the on/off switch to the back.My phono stage (also SS) doesn't even have a power switch.

If in doubt, talk to the manufacturer or authorized repair shop.

It sounds better when played for a little while, but I'd hate to have to wait for it to warm up - often times I'll just play a record or two.