Serious wear seems to be fairly uncommon, unless the bike has done a humongous mileage, as they are hardened steel and very tough. Chipped and broken teeth are more common, and due I suppose, to stones and grit getting in there. In the past I have repaired the odd broken tooth by building it up with sif-bronze weld, and then VERY carefully reshaping it by hand. I have also filled any wear corrugations in the sides of the slots in the basket with sif-bronze too.
Brian
