Tube gear sounds better as it warms up and operates and so does solid state gear so the longer you listen and leave it on the better it will sound. Cartridges are especially like this too they usually require between 4 and 6 album sides to sound right especially a low output moving coil.
rule of thumb: how long do you leave a tube preamp on versus turning it off then back on?
I just upgraded to an Audio Research REF 10 with 12 tubes and I am wondering how to best preserve the tubes. How long sitting turned on is equal to the wear and tear of turning it off then on again? I had a Rogue RP 7 with just four tubes so I didn't worry about this issue so much, I just turned it on when I began to listen then off at the end of the evening. Now I'm wondering where the sweet spot is? Away for a hour, two, three, turn it off when? Am I over-thinking this issue?