Leave it on?

I turn my gear off when not in use, and I have never had a tube go bad even after 15 years of regular use.  Of course, I cannot say that I would have had a shorter life for my tubes if I left them on all of the time; I have no comparative data.  There are many ways for a tube to fail, but eventually all tubes will exhibit lower emission of electrons from the cathode due to aging; turning off gear when not in use reduces this kind of tube degradation.  If an amp is designed correctly, the early failure from the effects of being turned off and on (e.g., thermal shock) should be reduced enough that it makes more sense to turn off the amp when not in use.  As for other components, heat can degrade some components and this will favor turning equipment off to reduce exposure to heat, but, some capacitors might fair better without being turned off if they are susceptible to damage from high inrush current.

The vast majority of tube gear manufacturers will recommend turning off gear when not in use.  The downside mentioned by those who don't recommend turning off their gear is usually not so much shortening tube life as it is performance is affected until the gear warms up.  The gear I am familiar with usually sounds decent after five minutes or so of use, but, I am aware of some gear that takes much longer than that to warm up (supposedly an issue with the capacitors taking some time to fully reform and stabilize).

I would go by whatever the manufacturer recommends. Generally, I leave most of my gear "on" or in "standby".  If I owned a Class A solid state or tube amp, I'd likely turn it off in the summer to keep from heating up the room too much but might leave them on in the winter. As noted, thermal cycling is what kills electronics or them getting too hot from the buildup of dust - so every once in a blue moon, clean your gear out carefully - or cover up the ventilation holes and slots when not in use if they are turned off. Streamers, your Wi-Fi router, and modem need to be rebooted every once in a while, to maintain a good connection and clear out any "cobwebs".  I do mine about once a month. 

I have done plenty of research on the subject. Fact is renewables are in place despite the fact that the best solution has been available throughout this whole mess. Check out all the important facts about efficiency and cleanliness and get back to me. So yes both at the same time, until it is time to change entirely to a modern nuclear grid. I think the correct solution is very obvious.

Remember that suggesting a nuclear solution is not denying climate change. 

Remember that suggesting a nuclear solution is not denying climate change. 

I have nothing against SAFE nuclear. Whatever gets us out of this mess that doesn't kill anyone is fine. 

Here’s a question — I relatively recently required a tube preamp.  I like to keep my amp and all components on and could leave the rube pre on too because the tubes last a long time and are cheap. The question is if I leave my amp and source components on and turn the preamp off is that a potential issue?  I know you’re always supposed to turn the pre on before the amp, but that’s when starting with everything off. I’m thinking it should be fine since the amp is already on but just wanted thoughts if any potential problems doing this.