Leaving amplifiers on all the time???

No good for global warming :0)

Tvad: Generally speaking, as long as gear is operated within its design parameters, it is not so much heat per se that damages or wears out electronic equipment, but thermal cycles experienced by gear getting hot and then going cold when turned on and off. That APL unit must be an extreme hot-rod design akin to a Class A power amp that passes large amounts of current at all times -- sounds like it needs heat sinking.

Many manufacturers will not advise in an owner's manual to leave gear powered up 24/7 due to liability concerns. Others address the issue by simply manufacturing gear with no on/off switch.

I have had my Adcom 555 pre-amp and amp on for more than 20 years, give or take a few OFF periods now and then.

I had a computer that I left on 24/7 for years it just got outdated. I don't do that anymore because of security issues. I thick with the only exception being power outages that my clock radio wich I must leave on has been working for 9 years. I still don't like the idea of spending another $400 to retube my Jadis DA-=60 I used the Gold Lion reissues they are great but not cheap. I also keep my very best 7316s in it and amd a pair of long plate Blackburn Mullard 12AX7s. I know it generally takes an hour plus to reach a good operational state but I almost never turn on and in the same day.