DACs/SS Pre/non Class A power amps/Streamers/Phono Stages can take many many hours to 'warm up', or rather, sound their best. My previous Jeff Rowland pre was said, by Jeff, to take several DAYS after switch on to sound its best. So, leave those pieces of equipment on 24/7 unless going on holiday etc. If one turnes such equipment off at night, and on when one wants to listen, even an hour before, you are almost guaranteed to NEVER hear your equipment performing at its best.
Tubed stuff warms up faster, obviously, but can still take hours to sound its best - it's not only the tubes, but also the transformers, which can take several hours to reach the optimum operating temperature. Previous QuickSilver Monos/ARC tubed power amps and EAR valve amps took c3 hours before they were up to operating temps.
This seems like a predominately 'tube user site', but I say that 'tube sound' and their limited lifespan, and the degradation of SQ during their life (power tubes), which is difficult to hear/quantify, and the fact that one tube will/may sound different to another, are some of the reasons I left tube use many years ago, not to mention that one never knows if they are really perfoming as good as they can, which, after initial burn in, will be a downhill slope - I almost resisted mentioning their inherrant distortion too! (waits for the bricks!)