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

When I owned a solid state preamp many years ago, it had to be on for about a week before it sounded right. Friends of mine with solid state preamps tell me that the week long thing really hasn't changed.

My current preamp is all tube and has to be on for about 20 minutes to sound right, and seems to get to where the warmup is going after about 2 hours.

Tube Research Labs builder and founder also told me it was easier on the tubes to stay on.  The way he used the 6sn7 tube in the preamp sure gave it long life and I did leave it on.  

Many amps and preamps have warm up cycles of a minute or less so that the tubes are brought up to full power slowly. How would this feature figure into the leave on/turn off debate?

It would figure strongly! My TRL preamp did not have this feature and the on/off cycling was indeed robbing the tube of more life than just leaving it on. Like all things audio....it always depends and few things are just black and white.

Wow...didn't expect this would be a debate, but it's a good debate. 

I used to worry about it, but these days, I really don't. Back when I had my quicksilvers, I just made an educated guess that turning them on and off more than twice a day was about the same as leaving them on, as far as tube wear goes. I could be wrong, could be right. 

Off and on IS hard on tubes...but, so is playing them. At idle...not so much.

Obviously, designs vary on how hard the tubes are driven, right? 

I pay my electric bill, I pay my taxes, and I pay for my stereo stuff. Sometimes I gotta leave it playing to break it in. Like doing laundry.