Warm-up time for amps and preamps

My Accuphase E600 sounds fine after 20 - 30 minutes. Sure, it gets better after awhile but that could also be attributed to a second cocktail. I used to sweat this stuff but not anymore. I just sit back, off center, and listen to all of my music. Don't sweat the small stuff. As long as it sounds great after it warms up you're in better shape than all the people that can't part with money for room treatments.

Class D 'warm-up' depends on the loop design. Bruno's work is quicker - think 1/2hr to 1hr. IR based amps can take several hours. Others like ICE probably should be left on. 'Warm-up' is an asymptotic curve, so there's no absolute # - these are just guidelines. Longer the better.

All audio electronics have 'memory' issues thanks to physics of the materials. Caps, resistors, wire, all dielectrics, active devices - all that stuff. Even speakers (mechanical equivalents of previous). SO any warm-up or low-level maintenance for sonic quality should be driven with an 'AC' signal with load(s). Static 'warm-up' has value, but won't provide complete results.

Caps failing under continuous bias is a design issue. Electrolytics are a special case as they do have (xxxx)hr ratings. If your equipment does not have these things (look for cans with polarity indication), run as long as you can prior to use. Infinite is good.

Tube amplification w/o 'standby' are incomplete designs. Tube filaments benefit from not being flipped on/off all the time. Commercial tube equipment (like in radio/tv stations) were always left on - standby off while the stations were off air. Studios, same deal.

I do worry about the lights being on all of the time and burning out prematurely. My concern is always about the power surge. Turning it on and off is probably the most stressful challenge to the capacitors, tubes, bulbs, etc. Any thoughts about this?

My system takes 30 to 45 Minutes to sound great! 

Great posts!  My Don Sachs preamp takes few minutes to sound its best and my McCormack DNA .05 Deluxe SS amp clearly takes a 30 minutes to sound optimally.  "Ear-lube" attributed to a beer or two might bias my impressions as "donjr"suggests above.  As a green-leaning guy, I can't bring myself to keeping my gear powered up 24/7.