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

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.

So do you recommend that leave my pre amp and cd player on too? Also, do speakers "warm up"? What about cables? If so, how long does it take? Thanks for the info everyone! :-)