Do I NEVER shut it off…?

I used to turn off my Plinius amp every two weeks when the cleaning ladies came just out of paranoia and immediately turn them back on after they left. When I talked to the Plinius service guy (yes there is one in the US even though their sales efforts have focused more or Asia/Australia/New Zealand) he told me not to turn it off ever - they don't go anywhere near the equipment, but I was worried just in case there was a new person in the crew.

They are very well designed and use minimal electricity when not playing. He said that powering everything up puts stress on the parts and will make the amp age faster. Of course he offered to recap and update everything in my amp (even though everything sounds better than ever). SS amps can last for decades without worry. That's the beauty of them - plus some sound really nice.

Other amps may not be as well designed - check with the manufacturer. Fans, tubes, whatever may have different recommendations. For me, I'd hate to have to wait an hour for warm up time. Often, I'll just play one record or a side. Turning everything on and off for that is nuts.

Leaving it on 24/7 is ridiculous!  Absolutely no science behind any of it!  Just peoples theories.    Turn on, wait 30 minutes to an hour to get warm, then enjoy.  Been doing this for over 25 years with some of the finest amps in the world.   Works perfect!  Pretty common sense here,  come on!

My SS equipment stays on all the time.

No need to leave amps on all the time, just turn them on for awhile before you are going to listen so they can warm up. How long that is you'll have to find out or take the advice of other owners.

I  have a pair of Class A amps that use up 300 W each when not putting out any sound. Keeping them on all the time would make the electric meter spin like a kid's pinwheel toy and would also turn any room they were into into a sauna in summer.