When to replace a crank?

[OakLeaf]

I wouldn't do a THING to that bike except tune it up and ride it. Wait until something breaks. Don't fix it if it ain't broke!

Karen

If the bearings have never been re-packed, the grease is now 20 years old and almost certainly not doing its job. BBs, hubs and headsets will last a long, long time if they get a little attention every so often and are kept in proper adjustment, but riding with dried-up grease is a good way to wear them out very quickly.

If you haven't seen (and ridden) the bike, you're really jumping the gun. It may not need anything but fresh grease, tires, cables and housings. It may need a lot.