Solid state power amps.; on or off?

Some people keep telling me that solid state gear should be left powered on all the time during day to day listening. They claim that thermal consistency will improve long term life and reliability. Power cost consideration appart, what is your opinion; experience?
There are two issues: sound and reliability. I've found that most Class A amps running over 100 watts, need a LONG warm up time (like a day or two). Class A/B and B amps don't seem to need this kind of warm up (neither do low powered class A amps). These can generally warm up in an hour or two. I have found some amps that do not follow this so well. I have a Classe Seventy that sounds great after only 1 hour of warm up, but I understand the Classe DR series (small wattage) needed very long warm up times--they also ran very hot. So you need to determine what sonic improvements you get over the warm up time. The second issue is reliability. I listen to music a couple of hours a day. I don't want to cycle the boards through the heating cycles especially on HOT amps like Krell and Levinson every day (I leave them on for sound improvement as well--but even if that wasn't an issue I would still leave them on for reliability). The only time they are turned off is if I am out of town for any length of time. The amps I use for HT only get used about 2 or maybe 3 times a week, so I only turn those on when I'm going to watch a movie. I only let them warm up about 15 minutes--which is probably less than they really need, but it's for home theater and I really don't think I can tell the difference for that application.
I leave my amp on all the time. A side story to illistrate the issue is with my Proton T.V. It's about 13 years old now and is used by our whole family, this means it goes on and off many times a day. Each time it's turned on the solder and electracal connections heat up and expand. Turning it off again the heated now contract. By cycling through thousands of times on our T.V. it final quite. I took it in, no problem with the componants, the solder joints had cracked. It was $250 to re-solder the mother board and power supply.
So my point is, in the extreme case we can see the damage done. Chances are you'll never own your amp for the approx. 5,000 on off cycles my T.V. experienced, but the same damage is done. The only issue I could see is if it runs in class A it could consumme alot of power just sitting, often times there is a stand-by mode for this issue.
My Classe' Ten has been on for 9 years without a problem. The only time it's shut down is component/wire change, contact cleaning and thunderstorms. No problems.
I never tried leaving an amp on all of the time until I read this thread and have started to leave it on now, I am a believer! After just a few days I have noticed a HUGE diference in sound in the most crutial moments, the first few minutes of listening actually sound good, go figure!
....any component that lasts 13 years with either no servicing or just one servicing is a gem. Craig.