I bought my Grado Reference cartridge from an Associate Professor at Michigan State Univ., and have been very pleased with it. His advertisement here on A-gon said the cartridge had about 100 hours, and from what I can tell that was accurate. I would not normally buy a used cartridge, but the MSRP on a Grado Reference was more than I could justify, so buying it used seemed like a good way to upgrade. It turned out to be an excellent buy. I recommend, however, that the prospective buyer contact the seller by phone and discuss the cartridge and its condition in some detail.
Buying used Cartriges
I quick gander at the classified section here on A-Gon will reveal that cartridges sell very well. How do you all protect your selves in buy something that you cannot verify the age and condition of? The sales are not being made with long term, high feedback members. Many are zero feedback users. Most sellers state, used "50-100 hours", with models that have been on the market for several years. I have made 3 cartridge purchases here on Agon and have been lucky so far, but am in the majority or minority?