New or used cartridge

Handyman, you mention an Urushi.

If you are considering rising in the Koetsu line, note that Koetsu likes to service their own cartridges by completely rebuilding them. It is said that they will not touch a cartridge which has been serviced by another.

Therefore, your options are limited. You could get someone (like Soundsmith) to inspect the cartridge, but not service it. Then, if necessary, send it to Koetsu for rebuilding at great cost. The result of this would be essentially a new Koetsu with Koetsu sound. Unless Koetsu refused to rebuild it because of tampering by the former owner.

Alternatively, you could get someone like Soundsmith to service it at lower cost. But you might not get Koetsu sound or Koetsu longevity.

I have the KRSP with diamond cantilever and like it a lot. Rebuild price will be very high - hope I can afford it come the day. But after 700 hours the stylus still looks good.

Terry9:  Thanks for the info, but there's nothing wrong with my Urushi Black. Just thought I would move up.                                          Steve

@terry9 
Consider having your Koetsu rebuilt through a Japanese or Asian deputy service. E.g. EIFL (Japan) advertises this for low-2000s on stone platinum model. Otherwise, the USA distributor & dealer will each take a hefty cut, and do nothing to expedite the process. Also, the rebuild cost does not rise for the premium stones, so the long-term cost on say a Coralstone can start to look pretty reasonable. 

I've also heard that Koetsu will not touch a cartridge that's been worked on by any 3rd party. Not sure if that still holds, but it certainly keeps me away from any 3rd part work. Over the years I've seen an awful lot of Koetsu with SoundSmith ruby cantilevers "less than 10 hours", etc, for sale.

@mulveling 
Is EIFL an authorized service facility? Their website does not specify.

I'm as guilty-maybe more than some, about not reading the initial question thoroughly, or posting "my" response before reading others. My Urushi Black is in very good condition. It doesn't need to be serviced. Just thought I would consider my options, as far as moving up the food chain.   I've seen where some retailers offer a trade in allowance of as much as 25%, but their prices are already inflated, so that doesn't mean much. May go up to a Jade Platinum. I need to go online, to get a description of the different sounds of each. If any of u can describe the different sounds of the upper line of Koetsu's, I will appreciate your input.