typical "shelf-life" of phono cartridges?

It depends upon the storage environment and suspension composition. High ozone like in L.A. attacks rubber fast. I live on an island off MA and the air is clean. We have salt air which attacks other things like metal. I have a lot of vintage cartridges and they are as good as new-30 years later!

Hi Nightdoggy - Glad to hear it.. It's been stored indoors away from direct sunlight, etc. and I live in the S.F. Bay Area so it's low humidity, etc. My '92 Toyota Tercel still looks almost new so I guess this is a good area to live for having things staying nice longer. The "o-ring" material where the cantilever meets the cartridge still seems to be compliant so I guess I'm good to go for awhile longer yet.. thanks for the feedback! jz

For a well set stylus, it's usually 2-3000 hrs of playing.
The rest is due to external conditions as mentioned above.
BTW cartridge manufacturers do specify a life span.

I emailed Grado this exact question and they replied there was no need to change cartridges because of this. They said you hear a loss of hi frequencies when you need to change cartridges.