Experience purchasing a used high-end cartridge

Trust but verify.

I recently bought a used Benz Ruby 2 from Wayne's Audio through US Audio Mart.

He stated he sells a lot of cartridges, he had several for sale, and good feedback.  He was offering several vintage cartridges that he claimed have fewer than 50 hrs. use and he's marketing his own MC cartridge.  He offered me a return privilege and installed the cartridge on my tonearm armtube.  He also gave me credit for a used cartridge I sent him.

The cartridge was carefully packed and works fine.  I've not felt a need to have it inspected, and I'm not sure there is anyone near me that would inspect it.

One advantage of buying a lightly-used cartridge from a trusted source is that it may be broken-in enough that you can judge how it will actually sound at its best; you can't always do that with a new cartridge.

I've done it, but only from trusted sources.  Can you return it?  Are they a dealer or an individual? 

Another thing to consider is cost of retipping.  If there is something wrong with it, or it's worn, can you have it retipped and still come out way ahead of the cost of buying a new cart?  One of my used purchases was a Van den Hul Crimson XGW Stradivarius, which at the time were fairly inexpensive to have retipped by the manufacturer.  I paid less than half the price of a new cartridge and have not had any issues with it to date.

Yes, but be very careful who you purchase from.  3 new cartridges that I purchased at used prices: VDH Colibri Grand Cru, Koetsu Coralstone D, Aida Mammoth Gold MkII.  

There is another method and one used by myself.

I sought out a Cart' in need of repair, which was a model I had already agreed a rebuild design for with a Technician from a Third Party Service.

I discovered a donor Cart' at a steal and took the Punt on the purchase.

The Third Party Service evaluation made it known the Cart' was in prime condition to undergo a overhaul but was filthy.

The end product Cart' fully overhauled cost approx' 1/3 of the Donor Cart's new value, and performs much much more to my liking than the Donor Original Model with a few hundred hours usage on it.