My rig is composed of items designed well enough so they sound great from morning start up, and since I don't necessarily listen closely before I've been up for a while I have no idea if the rig improves, but I don't care. I've, of course, come home after being out with the stuff turned off, but even then I generally do other things before listening. It's off all night, except for the "sleeping" REL subs as I prefer the electrons stay away from my gear when they're unsupervised as I can't trust pesky unsupervised electrons. Besides, my SEP tube amp deserves a break.