Always on ?

I am speaking from the viewpoint of an electical engineering consultant who designs audio gear for a living. It is true that thermal cyles will cause electronics to break down. The shock of turn on and turn off is even more dramatic. However, if the equipment is designed properly, neither of these should be a concern. If the gear runs hot, that is warm enough to put your hand on it and say "YO! that is pretty hot!" yet not burn yourself, then it should be off. If you have tube gear, it will sound a lot better the first 30 or 40 minutes if you leave it on, however their lifespand is dictated by hours of on time, regardless of whether they have signal running through them or not.

For my own equipment here at the house, I leave the solid state stuff on all the time playing FM even when I am not at home. I think my two dogs have gotten to love jazz now. For my tube gear, it is off unless I am sitting in front of it. None of my stuff runs excessively warm due to inadequate design.

By the way, if you put your hand on a piece of equipment and it runs so hot you can't hold your hand on it, get rid of it and buy something which is better designed. That piece will fail and there is no big mystery in moving heat away from electronics, they simply just didn't do it. Tube gear, of course, is an exception to this rule.

RobertD

If you are worried about lightening, then be sure to unplug everything. If your house is hit by lightening, it is unlikely any surge protector will survive to protect your gear. There is simply too much energy in lightening.

Speaking of leaving stuff on, the old Spatial Coherence preamp required 7 days to warm up, per the owners manual. Actually, it really took 6 weeks. If you are thinking this is a design flaw, you are thinking right. Of course, it only drew 4 watts so that wasn't a big deal after you owned it for a month.