HP and the like typically used high quality components in their instruments - these aren't consumer electronics that are built to a price point that we're discussing here. Given that, other than parts that are known to be problematic as a whole (such as the surface mount electrolytics used in 2000-ish Tek TDS scopes, for instance), I am disinclined to shotgun parts in them simply because <reasons> if they are otherwise functioning correctly.
I recently got a pair of old nixie DVMs from my favorite surplus place out in CA - they're siblings, both made by HP in mid-late 1969, and both sport most recent cal stickers from 1990, so I surmise that they've been out of service for nearly 20 years, likely stored in a warehouse somewhere. Both were initially powered up in short bursts, starting at about 15 seconds per minute on and then with slowly increasing on times - 20 seconds, then 30, then 50, then a minute at a time with a minute or so rest in between (I don't have a variac out there) to permit the long dormant caps to reform if they could, until I felt they could stay on without damage. One buzzed and flashed random things when turned on, never getting any better; the second settled in and seems happy as it was received, and eventually stayed on all through the night several times during my stay. Both have since shipped home and spent some time on the bench. The good one appears to be good straight out of the box - DC readings agree very closely to other meters, and the resistance readings are very close to the decade box settings. It still needs to be opened and wrung out, but I'd feel comfortable at present using it. The buzzy one has a dead filter cap - sticking another in parallel with the dead one got it operational with accuracy similar to that of its sibling. IT will be getting a new filter cap. I plan to open the other up and check ripple, but if it is in spec than it will NOT be getting any new caps.
I have several other 30+ year old instruments still running on their original electrolytics, too.
TL/DR - Unless there are known failures that are endemic to the particular breed, I replace parts in my gear when they go bad.
-Pat