[mwr2700]

When does the age of an amplifier need to factor into the purchasing
decision? I'm guessing at some point capacitors need replacing, and
other parts age to a degree that the cost of repair becomes prohibitive
unless it's got some sentimental value. But if you're looking at a $999
amplifier, what age would you say, it's just not worth it? 20 yrs? 40 yrs?

And by purchase, please consider it to be either a purchase to replace
a currently owned unit vs a purchase to buy a used model.

 

[wje]

More than likely, you should / could be able to expect 20 or more years of service. Right now, when it comes to stereo receivers and amps that were built in the early 1970s, most of those devices require a re-work of some of the electronics. The capacitors are starting to bulge, the contacts in the knobs and buttons need to be cleaned due to oxidation, etc.

Then again, I don't think I personally would worry about having the same headphone amp 20, 30 or even 40 years from now when 18 months seems about the current length I'd hold onto a product. But, if it were the Sennheiser Orpheus setup @ $55,000, then yes, I'd be concerned about how long it would remain functional if I were to keep it as my "forever" system.

 

[ilikepooters]

It wouldn't worry me too much, most old stuff it's all through hole components, and took me only 10 minutes on youtube to learn how to desolder.

A DAC would be different, i wouldn't fancy trying to desolder and swap BGA chips, tiny surface mounted components etc.