T-Bone: I figure that anything more than 8-10 years old is going to require some refurbishing to sound right (I'm talking tube gear).
I used to have my old Dynaco, Eico and McIntosh gear recapped every 8 years, or so, and my tube guitar amps @ least every 5 years (they always sounded better afterwards).
The only thing is that I am not familar with "modern" caps and resistors as the ones that I used were the same and/or close to the original parts (the last recap that I had done was in the mid 80's).
I need to recap a couple of 40 year old amps (that I have owned for aprrox. one year) and am concerned that modern caps may change the sound too much, though I don't see the point in placing 20 year old (plus) Illinois caps in them (which would sound similar to the originals).
Not much help, am I?