Amps

Solid state, O.K.

Tubes, No

However, I saw a YouTube about a guy (a New Yorker) who left a mono pair of McIntosh amps turned on for something like 35 years!

@dweller 

+1

I have left most of my solid state gear on for twenty years without failure… actually preferred. Some amps like Pass have a switch which reduces the power… but keeps them “warm”. Hence preventing the shock of startup.

My Audio Research tubed equipment slowly increases the power over a few minutes to reduce the impact of tube turn on. 
 

So, yes to @dweller 

op

it depends on the amp - what amp are you talking about

Forgot to mention the Mac amps were tubed! This guy had them stuffed under a bookcase or someplace he couldn't get to them so he just left them on.

Yes if they are SS since the caps take awhile to really sound good so leave the SS amps on and the tubed amps off but let the tubes warm up for at least 30 to 60 minutes for best sound.