What is the average lifespan of a phono cartridge?

@chakster 

that advice is not universal. Any stylus can be damaged and worn in far less time, depending on whether the arm is adjusted correctly, the overall treatment of the cartridge, and most importantly- the condition of the vinyl that is being utilized. A record that is full of pits and has dirty grooves will wear down any cartridge in a much quicker time. Some cartridges may last even longer than 2000 hours...depending on how they are treated, OTOH, the exact same cartridge may last just a mere fraction of that time.
Stylus shape is no guarantee of long wear. 

Well, i am not afraid of used vinyl and my interest is original pressings from the 70's. The benefit of playin used vinyl with Shibata, LineContact, MicroRidge, Stereohedron, MicroLine, MicroRidge..  is explained earlier in this post.

Conical stylus can't touch (damage) the area of the groove that Shibata can read easily. Even if the vinyl is slightly worn by previous owner during the 1970's it is most likely worn by conventional conical tip or an elliptical tip. Shibata can read the undamaged part of the groove on the same vinyl. This is the reason why i always buyin a cartridges with the most advanced diamond profiles. Another reason why i like the MM/MI is replaceable stylus, so i can compare used stylus to a new stylus by swapping them in 5 seconds (which is impossible with MC carts). For the same reason i like to try different styli on my MM carts to compare one cantilever/stylus combo to another. 

We're not talking about accidental damage, sh*t happens, i know. 
I believe an experienced audiophiles know how to set up a cartridge and a tonearm too. 

Simple FACT: LineContact type of the stylus has much longed life than conventional conical/elliptical, that's it. 

    

What's the best one can hope for, any stylus ? 3000 hours or so ?

I don’t know any audiophile who will stick to one cartridge forever, normally people sell cartridges before the stylus is worn out, but when we’re buyin used cartridges it’s nice to buy those with long life to insure ourself, it’s also nice to buy from a collectors who has many carts in rotation (then most of them have low hrs of use).

I can’t imagine myself using one cartridge for 2000 hrs, so i don't care. 
But i don't want to buy a used cartridge designed only for 300-500 hrs, especially the vintage MC which can not be retipped by the original manufacturer. The opportunity to find NOS stylus for MM is more optimistic. 

Dear @inna : If you want first rate quality level performances on what you are listening and want to preserve in mint condition your LP's then the ideal number is 1K hours and no more than 1.5K hours.

Could be interesting that a cartridge designer as @jcarr could chime about maybe not only me but almost all are wrong on the subject.

R.