Power Amplifier Longevity

My 7 pieces of 30-40 year old Bryston and Audire amps and preamps are doing great.  So are my 40 plus year old turntables and tuners. I did get Bryston to rehab the preamp.  It had a badly frayed power cord, and a very slight hum when turning up the volume enough to use a low output  M/C cartridge (because a house guest left my battery powered Audire head amp on and put new batteries in it backwards. It has finally been replaced with another one I ran into.   The only other issues I have had during this time were caused by me and my friend Johnny Walker.  Another amp and preamp are dead because of my ineptitude, not from material or design flaws..

I have a pair of Mac 1.2 KW amps any idea how long these will last

@jollygreenaudiophile2Talk about misinformation, you are full of it. Since when in the electronics world is heat a friend of ANY electronics?? Since NEVER. What are you talking about "transducers" in an amp for? Are you converting liquid flow into a 4-20 ma signal or pressure into a 4-20? maybe you are using your "transducers" to convert temperature into a 4-20 or a 1-5V signal. Give us a break. I refurb. vintage amps as a second income, caps don't just fail cus they "burst". most old caps are fine in a vintage amp, but a lot are way out of spec, some are even open with zero capactiance. This is why its standard to do the entire amp with new electrolytic caps to avoid any trouble later. 
To the guy who thinks using an amp is too hard on the caps, um... the opposite is true, show me an old amp that's been sitting in the closet for 20 years & how those caps are holding up. Old caps need to have voltage applied now & then, like reforming. Standard procedure where I work is to reform the large caps in a VFD every 3 years if they aren't being used or sold. I also use caps that are at least 10v higher in rating, using the 105 deg. for those in power section or near heat sinks.
Yea so I'm one of those guys who repalces a lot of electrolytic caps, but I work mostly on stuff that is from the 70s & early 80s, the good stuff. Both my Mcintosh power amps, one a MC2100 is still a daily driver since high school, are still running strong, so are all 4 of my Kenwood L-O7M's
So go buy some new equipment, if that is what you are into, spend 10K or more on a 7.1 channel for your TV, but its just a TV, not a hi fidelity 2 channel stereo.

I have a fondness for Class A amps and so paid a fair bit when one of them went south on me, but the particular model I have is quite rare so I didn't even think about not having it serviced. It was over 30 years old. I have two other amps of the same model still going strong, as well as an early Jeff Rowland amp (also 1980s) that still serves in my AV system.

On the current inrush issue, I have an early Belles class A amp that welded the contacts on the switch together due to that. After replacing the switch for the third time, I left it welded together and turn it on and off using a heavy duty power bar!