Do you leave your components on 24/7?

Never. I turn everything off.

Yes, unless I'm going on vacation.

My gear seems to sound great after 20-30 minutes. This includes tube and solid state. None of my gear sounds bad enough so I can't enjoy it while it's warming up.

Standby switches could be for different reasons. On a remote controlled unit such as a CD player, remote preamp, a standby switch may shut the remote receiver section of the unit off, that is normally needed to receive the remotes signal. On a lot of tube gear, the standby switch shuts of the B+, that feeds the higher operating voltage to the tubes. The filaments would stay on in this type of example, to keep the tubes warm, without the the wear, and extra electric needed. This is just a couple of examples. The purpose of this post is, even when you have a unit in standby (typically SS), the main audio part may be shut down, and cold. These examples aren't always the case.

No I do not;my cd player and pre/processor have standby switches as well as my tubed amps but they stay powered off
unless I plan to listen then they are put in standby mode and left there until listening is done.