Are 500 hours too many for a used hi-end cartridge?


I have been looking for good used mc cartridges on Audiogon in the $800-1000 price range. Most cartridges at this price advertise 20 to 200 hours. A few questions:
1. Are the advertised hours believable, since turntables do not have elapsed time meters?
2. Is cartridge age more important than playing time?
3. Is 500 hrs too high for the purchase of a used mc cartridge?


cakids
There is 2 main factors which can damage records nowadays and first one is more common:
- too low VTF
- damaged or misaligned stylus

If you have mono record which is shot, try it with true mono cartridge with 0,7 mil diamond or if you have religion against conical with 0,3x0,7 mil elliptical.  Just it must be true mono.

Hint these old mono classical or jazz records was played with 1 mil or even 3 mil stylus.
So you can try even with used cartridge just it have to be true mono. You'll rediscover that these dull records are still alive.  
@bukanona. Unfortunately, several of my old mono LPS are ruined due to a worn stylus. Now, I grant you, if you don’t mind a ton of snap, crackle and pop, then one could still listen to these...with the cartridges you suggest. 
@cleeds i am not happy to buy used cartridges with 500 hrs on them, i prefer NOS vintage cartridges or opened and tested NOS samples (this is the best) with something like 100 hrs max, from audiophiles (not from amateurs). 

But used records from 99% of the dealers most likely played with average cartridges for decades and if the condition is nice (fair grading) it's not a problem. 

I do not belong to the group of elitist audiophiles who comparing vinyl to digital and for this reason can accept only overpriced audiophile pressing re-issues with very limited choice of music on this format. 

I want normal records, originals, made for everyone in analog era, not today for audiophiles on re-issues that cost more than MINT originals 
Just purchased and installed a new A-T ART9. Very pleased with the sound initially. Can’t directly compare to other cartridges, but vinyl is superior in every comparison With hi-res digital.