Do you leave your components on 24/7?

Leaving a SS item on 24/7 is better for wear and tear. For tubes, tradeoff.
This question came up somewhere and after Googling something about it the fact was apparent that the #1 wear is repeated on/off cycling. worse than leaving it on all the time. So the only problem becomes is it worth it to you to waste the electricity?
Other than tube amps, which should not be left on for safety reasons and tube life. Tube preamps and other tubed low level signal devices can be left on, though if you are not using them every day, leaving on a tube preamp etc is a waste of tubes.
Since i am listening 10 hours a day every day now, i leave all my (main) stuff on 24/7.

The manufacturers of my SS disc player and SS preamps say to leave them on all the time (one of the preamps doesn't even have an on/off switch). My tubed CD player has a convenient switch that turns off only the analoge (tube) power while leaving the digital section powered up. Since it has only two tubes, I often leave both analoge and digital powered up all weekend since I listen at various times. My SS Class A power amps (300wpc) get very hot. Fortunately, there is a bias switch that can be used to lower the power and the heat. Although I generally turn the amps on only when I want to listen, having the bias switch gives me the option to bias down and leave them on for longer periods of time (although they still get warm). I have thought about switching to SS amps that can be left on all the time, but there are only a couple of A/B designs I would consider switching to. When I had tubed preamps, I sometimes considered the trade off between using NOS tubes and turning the preamp on and off, or running less expensive tubes but leaving the preamp powered up all the time.

You'll find this thread to be of interest. IMO, the conclusion expressed by Cathode in his post dated 2-8-11 is the best possible answer to this perennial question:

Depending on what kind of gear you have, how it's designed, and how you use it, turning it on/off vs leaving it on is truly component specific; making a blanket recommendation is not possible.... FWIW - I work as a reliability engineer in the semiconductor industry.

Regards,
-- Al

I leave mine on all the time, even the amp with Nuvistors. But I wouldn't leave a Class A amp on. My line stage has a standby as it has a Class A circut. I also have protection in case of storms when I am not here.