How long should a cartridge last?


I have a Shelter 501 that started acting up (skipping...I also didn't set my new arm up properly). The folks at The Analog Room said I needed a new cartridge, which I just got. So, my first Shelter lasted about 3 and a half years and saw very regular use, perhaps an hour a day, maybe more (on average). Still, I was surprised it went kaput so fast. Do folks typically just buy a new cartridge (as my dealer recommended) or just get a new stylus? I did not quite understand the explanation...the "suspension when out"...I could call my dealer and ask again, but I thought I would post here and see what other folks might say.
mcmprov
The ones I have had done sound fine. Exactly the same as before? Doubtful, two new cartridges of the same model seldom sound exactly the same. But well worth the expense; there is a good chance that they will sound better than before but that is a separate question. I am an unusual dealer in that my orientation is toward the customer spending the LEAST amount of money for the sound he/she wants. Since I don't depend of it for my livelihood I can entertain such an attitude. If you still have the old one I would either advertise it on here as in as is condition for some else to buy and have repaired or do this myself to have on hand as a spare.
If you keep your records clean and set up properly, 4000 hours or more is possible. MM cartridges do have an advantage in that the stylus can be replaced, but i have a frog cartridge that my daughter is currently using that goes back to 2003 and i brought it used so i do not know the exact hours. It was used for 3 years as my primary cartridge before i got an airy3 and my daughter has used it for 3 years as her main. I checked the tip two weeks ago and the stylus is showing very little wear. Suspension still seems firm and the sound is still excellent.
I easily set up the VPI Scout by myself. When I tried to put a Graham Phantom on Aries, one problem I encountered..the Furutech tone arm cable could not fit very well into the hole in the plith...the 90 degree din was just too large. I think it was bumping against the plinth. I eventually adjusted it and got it to fit into these very tight quarters better. Anyway, not understanding this, I set the tracking force very high. The records kept skipping and I had thought the tracking force might be the problem. Ooopps. So, that might have shortened my cartridge life. I guess that might have been what happened.
cartridge set up is a major factor in cartridge life as well as record life. IMO, too high or too low on vtf will cause problems. i prefer to work on the light side on VTF because the universe responds so well to the lighter vtf. Also "dropping" the cartridge down on the record will stress the suspension.
>>09-18-10: Oilmanmojo
IMO, too high or too low on vtf will cause problems<<

Actually more damage occurs if VTF is too light than too heavy.

Many folks find that counterintuitive, but it's a fact.