Cartridge new or used ?

To answer the actual question, none of us is qualified to judge the difference in appearance between a new stylus and one that is lightly worn. No matter how powerful the microscope. That takes experience and skill. Also, most brick and mortar dealers are honest enough not to sell you a used cartridge in the guise of new. And finally, a never used cartridge that is 4-5 years since manufacture is going to be just fine. Many of us own NOS cartridges that are more than 30 years old, and we’re happy.

Disgusting.

I've got a lab grade microscope in my workshop, and I use it to look at styli from time to time, just for entertainment value.  The conclusion I draw from looking at new cartridges, cartridges I bought new and which have been used only for a few hours by me, and cartridges I bought used, is that I would not trust myself to evaluate stylus condition, articles from the internet notwithstanding.  If I needed to check the condition of a stylus tip, I would send it to Peter Ledermann and pay him for his time.

I am surprised that this discussion brings out such passionate disagreements.  I think I've written elsewhere that I would happily by a used cartridge from someone whom I knew and who was in my sphere of friends, either on this forum or local to my residence.  I would not send big $ to a stranger in a foreign country for a used cartridge, however. eBay scares me based on my bad experiences buying vacuum tubes, and rarely LPs, off eBay.  On the other hand, the capacitors that come all the way from the former Soviet Union (Russia, Estonia, Ukraine, mostly) via eBay have uniformly been great.  Like Chakster, I much prefer to buy NOS, if I am in pursuit of a vintage cartridge, but I've got so many now that I may spend the rest of my life evaluating what I've got.