nowadays only buy based on how the frame condition and fit- maybe the wheelset. 90%+ always needs to be rebuild or replaced anyways.
Do you really expect to have a great, safe experience dry BB & hubs and 30 yr old brakes cables?
Things I needed to replace immediately on every bike I have bought:
chain, brakepads, seat, pedals, BB spindle(sometimes) & lube, wheel hubs bearings & lube, headset, cassette, chainrings (sometimes), tires (always), tubes (always), cables, housings, hoods, tape.