I agree with everything Dwight says in post 5.
I think the point is that every repair on any vintage electronics should be a targeted repair. Which means, for the most part, unless there is physical damage (such as cap leakage, overheated parts etc that gives the game away) the fault should be assessed where possible with the aid of the meters & scope and the schematic.
Only when there is adequate suspicion that a component is defective should it be removed from the pcb and replaced. A bulk replacement of components, like caps, is not logical or necessary and in less skilled hands runs the risk of introducing faults or pcb damage. It is good to keep vintage pcb's as original as possible and free from physical damage. I'm nutty enough to replace TTL IC's with ones of similar date codes to try to keep originality.
It can be surprising sometimes how good vintage electrolytic capacitors can be, especially if the item has low hours that is. One example is an IBM5155 power supply which I think was probably close to NOS. Not a single electrolytic in it is defective in any way. So it would have been a really bad idea to bulk re-cap it and the electrolytic capacitors in it may well be better quality than many we are seeing today.
The only time I break this targeted repair notion is when I see surface mount electrolytics in typically 90's vintage gear, like the logic boards on my 2465B scopes. I replace those on sight as the leakage is very destructive to the pcbs, and has already destroyed a good number of the A5 logic boards in these scopes. I can barely believe these capacitors are still popular. The A5 boards fitted with radial electrolytics, or tants, never have any issues.
The leaked electrolyte destroys tracks & components is a zone that extends far from the leakage:
http://worldphaco.com/uploads/TEKTRONIX_2465b_OSCILLOSCOPE_A5_BOARD_REPAIR.pdf
Also, if you see a pcb with an array of capacitors of some brand and age of electrolytic cap and even just one has leaked electrolyte that means the others probably will too in the near future, so in that case replace them all is a wise move. Dome topped dried out caps reading high ESR and low capacity, especially near heat sinks etc should always be replaced. In any case, it is a judgement call.