does your system "warm up" and then sound better?

You can do this with SS components which have insignificant idle draw- when leaving them on all the time. They generally do sound better than cold components
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You can't do this with with tube gear because even the lower current on the tubes will still age the tubes and you'll burn thru them at an unacceptable rate. I have good NOS preamp tubes in my amps which I hope to preserve for as long as I can, so I never like to see my amps on when not in use. I have mistakenly gotten distracted and found them on much to my chagrin.

The Answer is no for tubes Yes for SS.

Mechans, the answer to the OP's question would be yes to both SS and tube amps sound wise, would it not? A good 2 hour warm up for tubes is a must anyway. Lots of class A SS amps are better off with a warm up period also, cost wise. Unless you double up your amp as a heat source. Any component will sound "better" fully warmed up. More like at it's "best".

Yes, I find especially when listening to vinyl, that the cartridge requires one album side to come out of it's hibernation mode. I feel that the amps and pre-amp get better as they reach operating temperature as well.

I leave ss components on 24/7 (in low power "sleep" mode if available). Tubes I fire up at least 30 minutes before I start listening. I do think things sound better after listening an hour or so. Theo's observation about cartridge performance is interesting. I'll have to try and see if I hear a consistent improvement listening to the 2nd side of the first LP played in a given evening.