Class A amplifiers

Boulder 2060.
Still reliable.

completely false statement.  Been repairing amps for so long now it comes down more tot the quality of the parts then the heat if the units are vented correctly and they have good heat dispersion.  Any old component you purchase probably needs a parts upgrade. Last night we compared three class A amps Coda, Carin and BEL.  We were surprised with how well the BEL amp sounded.  Very musical sounding amp built in the 90s.  Still going strong although I think changing a few caps is a good idea, I also think the Nichicon PS caps will sound better along with Audio Note resistors and capacitors or Amtrans.

I have been repairing, modifying and building audio components for close to 30 years now.  Don't worry to much as the caps, etc., can be easily changed.

I have a glorious Class A Sugden A21SE and it never misses a beat, I contacted Sugden and asked them about having it serviced and he said it’s likely not to need looking at. 
In my opinion class A can’t be bettered. 

As others have mentioned, it depends.

All Class A run warm. Many run hot. Some run so hot that they dry out the electrolytic capacitors.

Solution: don't run them hot, use electrolytic caps only in the power supply, and isolate those caps from the heat sinks. Personally, I run the amplifiers' heat sinks at comfortably warm and the power supply at room temperature in a separate rack in another room. That's a bit extreme - but not as extreme as George!