Class A Power Amp Degredation

Dear Forum Members,

I've read in several places that because class A amplifiers run hard all the time and most people don't cut them off, they wear our faster. Plus, because they remain on all the time they burn much more electricity and generate lots of heat, some more than others, at least that's what I'm told. I wonder what happens if I have to go away for a day or two?

I can't afford to purchase a brand new class A amp so I wonder if I should even consider the purchase of a used Mark Levinson, Pass Labs or other class A amp? The only amplifier I know of that can be switched between class A and A/B is the Plnius. I am told that this amp only run very hot when it's running in class A.

Here are my questions:

1. What should I look for in a used amplifier?
2. Do class A amps wear out faster than other amps?
3. Are there amplifiers that can match the musicality, sound staging, bass and sweet sounds of a class A amp? In other words are there any class A/B amps that have all of the quailities of the class A amps?
4. If I do decide to buy a class A amp how far back in years should I venture? Right now I am considering the Mark Levinson 27 or 27.5 or Pass Labs X150/250 and X150.5 and X250.5 amplifiers. It's been suggested that the Mark Levinson is more musical????? I just want to get the best amplifier to run my audio system.

I will be driving Magnapan 1.6 speakers which does require a fair amount of amps/power to drive them. Also I mostly listen to classical music, large/small scale choral works, contemporary and gospel music and all modern jazz. I love the human voice. I also love a huge sound stage with lots of depth perspective.

Any assistance and suggestions you can provide will be very welcomed. Thank you so much for taking of your time to respond to this plea for help.