If someone walked off the street with an old 10 speed with a loose ball and cup BB which probably does not have a sleeve I am going to tell them "you NEED a new BB".

As they stand there asking me "how much to fix my bike" my options are to charge them $30 to spend half and hour opening up their BB and putting it back together with new bearings and grease and it is probably pitted anyway, or to charge them $15 labour plus $17.99 for a new cartridge unit which I can guarantee will last at least a couple years. I cannot guarantee them anything regarding the old one because I have no idea what it looks like inside, but I can guess it's not good, and I have to charge them to open it up to check condition in the first place. Once you think about it makes a lot of sense. I am guessing if the OP had his bike in the shop looking to have work done he does not have the tools or know how to overhaul his BB in which case I support his LBS mechanic in the recommendation that a new cartridge unit is his best option.