Turn that thing off when you're not around, you wasteful boneheads! I think the "warm up myth" has ensnared too many at this point, and lends credence to the question: Do you listen to your gear or the music? If everybody tells you their gear heap sounds better after being left on for 37 hours, you tend to jump on that boat...and as we all know, no serious gear head EVER turns their AC wasting precious pile off. Unless it's tubes where somehow the Tube Head gets a pass. I not only pass on this, I turn off that road entirely. Example: I keep my phono preamp off all the time (except when it's pressed into service) as it presents an otherwise unnecessary signal to the inputs, that bugs me, and it's my personal cross to bear. The other day I HAD to listen to Lowell George's solo LP and although my pre was only on for exactly 18 seconds prior to the needle dropping, I enjoyed the living crap out of the LP. Would it have sounded better with electrons running around the phono pre for the geek designated appropriate warm up period? Maybe a tiny bit, maybe not so much that any sane person would wait for it...but so what...would I have enjoyed my hero, Old Dead Lowell, more? No. My tube amp sounds great all the time (as does the SS stuff in front if it), from turn on to turn off, and the degree to which any of this may sound better from warm up is far less than the effect of my ever changing mood, ear wax buildup, ambient humidity, the sequins on my cowboy shirt, my rock hard pecs, and the sound reflected off the back of the butler I use as a footstool. I say "tune in, turn off, drop out."