I would recommend leaving your amps on 24/7 for best sound quality. Solid state gear takes even longer to warm up than tube gear. I think the bigger the amp, the longer the warm up. We had a customer from Portland bring a DK Designs amp to audition some of our speakers. Huge amp, tons of power (at least 150w), sounded awful when we turned it on. Which was kinda funny because he just paid $1400 for it on eBay (msrp $3250), the remote's input selector didn't work and it didn't have a power cord (none of which was listed in the auction). It was the first time he opened the box up. He didn't like the amp and left it with us for the afternoon to play with it while he had lunch with friends down here. To get to the point, it took every bit of three hours of continuous playing before we could even take it seriously. It continued to improve throughout the afternoon. By the time he left late that afternoon, he was happy with the amp and had bought a set of speakers.
If you consider a typical listening session of maybe two hours, a beefy solid state amp will not have the time to warm up, leaving you little opportunity to enjoy the potential of your amplifier.
my .02,
Chris