Take it to a specialist with a good microscope. The specialist can tell you the condition of the stylus, the suspension and the magnet coil assembly if it is a "naked" body cartridge. Retipping and rebuilding cartridges are expensive services. Caveat emptor. The cartridge could have been dropped, dragged across a record, bounced off the turntable or misaligned in the tonearm.
Would you pay more than 25% of MSRP for a used cartridge?
Seems most seller want to price their "low-hour" used cartridges at 50-80% of MSRP. This seems ridiculous to me because there is no sure way to verify these "low-hour" claims. You need to have specialized microscopes and even then it's a just a guestimate if worn or not.
Another point is even a cartridge with 1000+ hours can still sound very good. A worn stylus will mistrack only on certain passages of certain demanding records. So it is nothing obvious.
So why do all these folks price their used cartridges so high? Are folks actually paying these prices?
My max. would be 25% of MSRP for any "low-hour" claim.