...or not. My experiences here are dismal, in that the shop staff neither have the experience or time to properly service a cup and cone BB, so their natural inclination is to pull out all of the old and slap in a UN26 (or worse) cartridge unit. For $50 and add another $50 in shop time.

Then there will be about a 25% chance that the spindle length of the new unit is correct, leading to problems with the chainline and the operation of the front derailleur.

The shop is highly motivated to use existing inventory, meaning that they'll likely install a unit meant for a triple MTB crankset, resulting in your crankarms sitting a full cm too far outboard on each side.

Properly servicing your existing loose-ball unit will be far cheaper than a replacement. I have overhauled hundreds of old BB's, and I have only seen a very small number that were so profoundly neglected that they couldn't be revivived with $5 worth of new balls and some fresh grease. Perhaps a new spindle as well in the extreme cases... add another $5-10.