Just thought I'd touch a little on this subject, alot of people have mixed feelings about it but I always leave my Albarry's and cd player on I've read else where that the constant change in temperature from warming up to cooling down can shorten the life of your Caps and valves along with other bits and pieces, I've also noticed a good change in sound when my hifi has been left on as appose to warming it up for an hour before every listen, of course there's the other side to it such as burning through electric and the obvious danger of leaving things switched on