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
cakids

In so long as the cartridge has been well cared for and properly aligned, I believe you should be safe.  A good photograph of the stylus at close magnification would be useful. 
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Thanks again for your comments. The posters seem divided on pro-used cartridges vs anti-used. Taking all your thoughts into consideration, for me, at this price range, I’m probably going new with an AT ART9, to minimize variables. Also to have a local human to deal with if there are problems.
Happy listening.
PS I may have a slightly used Hana EL for sale if this works out (somewhere between 50 and 200 hours of use I estimate). Or maybe I’ll just keep it.
@cakids You don’t need a local vendor, you need the AT’s distributor support so you can give your cartridge (when it’s worn) to the distributor of the Audio-Technica and he can ship it back to Japan. Audio-Technica do not repair cartridges, they do not re-tip cartridges, you will get a brand new cartridges with their exchange program (for about 60% of retail cost), only if you have valid serial number and if it was purchased from official AT dealer/distributor in your region. Don’t buy grey market samples, they will never service them.

Forget about re-tippers, this is not the same.

Stay with Audio-Technica to get full support from their distributor, this is much better, believe me.

When one ART9 is worn they will give you another if you send yours back, new cartridge with new suspension is much better than third party re-tip. Or maybe you could even upgrade to ART-1000 one day, if they have upgrade program. Only official AT distributor can help you with it. 
I think enough people have answered to confuse you on buying used or new. I want to share, instead, how I keep track of my cartridge hours. I once purchased a box of hand tally counters (the sort that you see where places are trying to count how many people have entered.) Maybe 12 bucks for a pack of 6 on Amazon when I acquired them. 

 With a label machine, I indicate the cartridge and the date I acquired it. Then, every time I play an album side on that cartridge, I click the appropriate tally counter once. This may sound onerous, but between using a carbon fiber brush, some blue tak on the stylus, and pressing the tally counter probably requires 20 seconds maximum. More like 10. It’s a worthwhile routine to develop and keeps needle and vinyl in excellent condition. (This assumes you first cleaned your vinyl properly on acquisition). It’s just like brushing your teeth—proper habits preserve health and money. 
I then divide by three to give an estimate of the hours, knowing that this will yield a slightly higher number since few albums sides are a full 20 minutes.

Then you are empowered to decide how many hours a given stylus should last, or when you need to scope the stylus. Simple.