Buying a used cartridge...tell us your tale.

Personally, I have a VERY BIG reticence to buying a used cartridge. The amount of use or damage to the stylus and/or other working parts would seem to me to be a large unknown. Since just one play of a damaged stylus will result in damage to your records, I have always shun away from any used cartridge purchase.
OTOH, I'm sure many have been successful in buying a used cartridge and then again...there are those that have NOT:(.
I would be interested in hearing the tales...the good, the bad and the ugly