Cartridge new or used ?

https://losslesssound.wordpress.com/2018/12/24/using-macro-photography-to-check-stylus-wear/

This article explains how to check your stylus. 

Hi @chakster,

Damaged or worn diamond looks different, but to inspect them we need a powerfull microscope, this is an image from the internet, the diamond is worn accodring to the poster.

Great photos in your earlier post, and I agree with you about the resolution level necessary to learn anything meaningful about stylus condition.

I would estimate you need something on the order of 1000x to perform a meaningful stylus inspection.

The linked photo was taken at 240x, using the microscope I use for setups and it’s clearly too low magnification for inspecting styli.

https://galibierdesign.com/stylus-01/

@stevecham - your estimate off 40x is off by just a wee bit ;-)

Cheers,
Thom @ Galibier Design

 @thom_mackris   What can you tell us is the actual shape of the various facets of the diamond, before and after damage? Because, IME, without knowing exactly what you are looking for in this regard, all else is just a guess. So even with a 1000x microscope, the knowledge of the shape is crucial...which is why I suspect Raul and I state that only the manufacturer of the particular cartridge knows this for sure. 
i noticed you recommend Magik eraser as the stylus cleaner, very interesting. 

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.