Cartridge new or used ?

 @chakster   None of the photos that you posted have any meaning whatsoever. The first stock photo by AT is a generic photo with just one face showing...and none of the rear facets and the actual cut angles, worthless. The other photos are equally as worthless, showing a stylus at that magnification is totally meaningless...well done, lol.
@clearthink.  +1

chakster, if you don’t believe me, read what stevecham wrote above. Your ’advice’ is going to result in folks damaging their LP’s...unfortunately. . As i stated before, I am certain yours are damaged beyond repair at this point, as your vintage stylus is nice and sharp!!!LMAO! But, that’s ok, keep on with the great ’advice’, :0(

@uberwaltz. Why would anybody sell a perfectly decent high priced cartridge like a Koetsu RSP at 17% of retail? Oh, I forgot...in order to get that cartridge factory reconditioned, you are going to have to send it Japan, and depending on whether it was a grey market item or whether it already had a bastardized stylus, (in which case you will be out of luck entirely) pay $1000’s to Koetsu for their services.
Unless, that’s not correct, and somebody just happened to feel ultra charitable to your friend, lol.

chakster,, there is a very big difference between a cartridge that has been well taken of by the original owner and one that has been worn out and possibly damaged by the prior owner. Obviously, as a cartridge is used, it wears, IOW..it is a wear item. The question is how it was treated in its past, not that it is wearing as we play it.IMO

I have some questions for all of those folks who buy used vintage cartridges, or used non replaceable stylus cartridges...
how do you know the condition of the diamond? Do you look online and get a generic picture that may or may not correspond with the stylus shape you are expecting to see, and are you able to actually view all of the facets of the diamond..on all sides, or are you doing something else? Using a high powered microscope? Are you able to determine the exact cut and angular correctness of the facets? 
Some other method to determine wear and condition? Do you have any idea as to the condition of the suspension and what that is supposed to perform like...or do you not care about this aspect that much, and assume all is as it was from the factory originally?

@rauliruegas You bring up a great point, and one that I agree with 100%. That point is that the factory really is the only one to truly determine the condition of the stylus/suspension. The various stylus/cantilever manufacturers know what it is that they manufacture, and what the facets of the diamond should like, new and under basic wear patterns. This is really the point that I have been trying to get across, and I think your post said it very well.

 @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. 

@thom_mackris   Thanks, that does clear up your point. We are in total agreement.