Do you leave your components on 24/7?

Banquo363...In that case, I hope you plan ahead so you are sure to be at home on day 365.

Inna,
If there's hell below, we're all gonna go.

Paperw8,
You describe leaving the components on as 'massive waste'. If there's no signal, consumption is low. Give me a comparison if you can: Is a SS device on (no music) the equivalent of one 100w light burning? A tube device equals two 100w lights burning?

As far as equipment sounding better if it's been on long, or even after burn in, I personally would have a tough time telling. The combination of a lack of commonly understood detailed descriptors to apply to sound(what is bright, anyway?), and the difficulty of accurately retaining in memory the first soundscape to compare to the second, make it hard to tell the difference. I can only feel confident in hearing a difference if I do a rapid A/B switch. I just installed a Porter Port. Does my system sound clearer, more articulate, wider soundstage? Hell (Hi Inna), I don't know. It sounds pretty damn good, which it did before. But the outlet I removed was clearly inferior, so in my head I know there's an improvement. I just can't hear it. Sad, but not atypical, I'm thinking.

I have a VTL preamp and the manufacturer states that a new set of tubes from them will last 5 years. Nothing mentioned on what the average time a consumer will have the preamp powered up. I leave it powered up most of the time mostly for sound quality so maybe that time (5 years) could be cut in half. My amp is solid state and it is never turned off unless I change interconnects.

Paper ... You may claim thermal switching is B.S. but several manufacturers of equipment I own as well as my long time dealer tell me that leaving things on reduces brake down rate , Iv'e followed there advice for many years and have found this to be true. What do they no eh . Do you no a manufacturer of S.S. equipment that states otherwise . Class A amps that run very hot may be the exception .
And as far as a sonic difference goes , my own ears as well as other well respected audiophile friends have tested the affects of turning off large power amps and the results are consistent , etched sound for hours to days , one of the few things we agree on . Have you done such tests for your self , Or are you a theoretician .

The link to a post Almarg pointed out covers the way it is IMO. Some electronic components (semiconductors) do not like the big thermal swings, and may fail sooner. Others may settle, and break in to the on always operation since they stay hot all the time. With this case, those semiconductors may break when they shrink during cool down, since they have never been allowed to contract during a cool down, and expand during warm up, since this is what they have become accustomed to. Think of it as a super miniature bridge without expansion joints, for thermal change, while others may handle the temp swing like a bridge. That one poster is an engineer(Almarg link) that specializes in this. And like he says, it varies from component, to component. I'd have to agree with that. It makes sense.

For those of you worrying about going to hell... Maybe one of those inventors of those little magic things that change the sound so much your jaw will drop, may figure out how to
air condition hell.