How old of McIntosh SS stereo anp

Just curious, how old of McIntosh 2 ch SS amp, if well cared for, would you consider to purchase and not be worried about needing service? Of course, things happen, but in a general sense. Many say if buying older amp, replace caps, etc. I’ve also heard that Macs rarely need service and should provide lifetime of service if taken care if. With that said, I hardly believe that older equipment does not reach a point that it needs service.  Maybe a place like Audio Classics may be ideal. Opinions?