Does anyone leave their amp and preamp on all the time?

No problem leaving Solid State gear on,  yes, class A gets hot and can raise the electric bill a bit.  
I agree, it sounds better leaving it on.  In fact,  even though a cold amp sounds better after 45 minutes, I contend that it can take weeks on some amps to reach their potential.  

That's all very helpful. I never considered the fire risk. My preamp has been modified and there is no off-switch. I could pull the plug I guess. I am looking for a bigger Bedini to bi-amp with. I have a 100/100. That amp ran very hot and I didn't leave it on when not playing. That was when it was working.  I tried to update caps myself and messed something up. Its been sitting for 2 years now. Maybe my next post will be about where I can get it fixed. Thanks for the responses.

I do not leave my equipment on, as my amp and preamp shut themselves down after so many minutes of idle time and with a power unit, DAC and transport, consumes quite a bit of electricity.

It does take 10-15 minutes of play time for my equipment to sound its best.

Preamp no but my amp is always in standby.

My mono blocks consume 230W each in standby mode, so I turn them off after use.  I will turn them on a bit before I plan on listening to warm up and usually by the end of the first side of an LP it sounds just fine.