Cartridge aging and tip wear symtoms?

I have had my Benz Ruby for a couple of years now and while it still sounds great; I am wandering if anyone can
definitively say what are the symtoms to look out for in regards to the diamond tip beginning to wear.
Im a novice. Surface noise is a sign. Also the cantilever will loose some suspension. That will mean a bumpier ride and more wear. I also would like to know if benz lasts any longer than others. I have an L2
If you can hear surface noise or any other effects of stylus wear, you've probably already done permanent damage to your vinyl.

Assuming clean vinyl and proper setup, the main factor in maximizing stylus life is the size and shape of the stylus. The larger the contact area, the less friction at any given point and the longer the stylus will last. Conical (spherical) styli have the smallest contact patch (theoretically a geometric point) and therefore the shortest expected life. Elliptical styli are better. Line contact stlyi are better yet and micro-ridge styli should last longest of all, since they have the largest contact surface. The makers of a few, high end micro-ridge styli even go the extent of aligning the ridges with the molecular structure of the diamond, which makes them significantly more resistant to friction.

Stereo shops used to have specialized binocular microscopes for stylus inspection. Even with that it takes a trained eye to know what to look for, and fewer shops have those tools and skills any more. We have one locally but many cities do not. You could consider mailing it to the manufacturer or one of the respected retippers, like Soundsmith for example. They'd give you an honest assessment.

An audio signal analyzer or software could probably be used for this also, assuming you had data from a new sample of the same cartidge to compare. A worn stylus would start to lose HF response, beginning with highest frequencies the cartridge can reproduce. The more wear, the more this would progress. You can't wait until you hear this however. Most cartridges extend well above 20KHz, so by the time you noticed HF rolloff much damage could have been done.
I am quite happy with an original Fidelity Research Mk13F, into a Sutherland PHD on a Rega P9.
I bought the cartridge brand new back in the 1980s and I firmly believe it sounds better now than when new, but of course all the ancilliaries are better.
No noise issues or cantilever failures,is this a fluke or do they just not make them to last anymore?
distortion in the inner groves
There's no distortion in the inner grooves when playing the old FR cartridge.
An improperly set up cartridge that is brand new will have distortion in the inner grooves also.
Closer inspection using powerful magnifying glass or jewelers specs would show obvious stylus wear, especially on either the right or left side of the tip, indicating that the cartridge was mistracking for quite some time.
The cantiliver they say can loose it's stiffness over time , but so far after 20 years the FR is still strong.
Dropping the arm on the record not lowering, and tracking at too high a range can lead to cantilever fatigue in a brand new cartridge.
If everything is set up to spec and there have been no mis-haps,and still lp's just don't sound as good as they once did, time to invest in a new cartridge and make sure it is compatable to your arm and set up properly.
Most cartridges fail because somewhere along the way,an accident happened.
Frequently the suspension will give up before the diamond ever starts to show wear. Doug is right, unless you have the proper stereo microscope it's almost impossible to tell how the diamond is wearing. I used to do it, and what I would typically find is dirt! Back then, most people didn't practice proper stylus cleanliness, so you ended up with a pack of crud on the end of the cantelever. Once that was cleaned up, then next thing was the impact of improper alignment / anti-skating. Many stylii would show uneven wear. But a properly aligned, properly maintanined (including clean records) cart ridge could last a couple of thousand hours. Most people replaced carts because they wanted something new long before their original cartridge wore out.
I've viewed many needles under the scope over the years. Rarely did I see one that was actually worn. I did see a few where the stylus had been sheared off of the cantilever... and a lot of dirty styli :)

As the cartridge ages, usually whether it is played or not, the cantilever suspension will perish. As this happens, the cartridge will begin to mistrack; often it will sound harsher. With most cartridges 2-3 years is about all you can hope for before the cantilever has to be refurbished.
20 plus years on the same mc FR cartridge and no sign of cantilever distress.
"with most cartridges 2-3 years is about all you can hope for before the cantilever has to be refurbished"is enough to scare a lot of people away from vinyl.
I'll wager I am not the only person with an oldie still working.
Or am I?
Any other survivor stories?
A worn out cart will start to distort on the inner groves.Its a symptom.I know i have had it happen to me.
You can certainly get a lot of cartridges to play for years. But- they won't sound right nor will they track right. So far I don't know of anything that lasts forever, although in terms of recordings, LPs are probably the longest-lived media.
Sibilance, inner groove distortion, high end roll off.

Of utmost importance is keeping the stylus clean. Do a search for the "Magic Eraser" threads. There is nothing comparable to this inexpensive little gadget.
I just got a new cart. and have to go thru all the "break in" time that others claim. I had a used MC that I thought sounded pretty good, it might have been at least 20 years old but with little wear. It did not have any symptoms of old age that I could detect, tracked well and no distortion. Well I decided to put it on ebay and now perhaps almost regret it. The buyer took a long time to pay. I was almost hoping he was a non payer so I could change my mind. No matter, he came thru eventually and I shipped today. I expect to get the long life from this new MC. Well be glad you don't have a Victrola. The needles were good for exactly one play each, if the steel type! I have a Victrola and they still make the needles for the wind up acoustic things! Direct to disc, no electronic distortions. So must sound great!
The 20 year old Fidelity Research Mk1 3f shows no signs of distress when I play track 5,Cartridge tracking tests on the Audio System Test Record(Nat'l Research Council of Canada).
No loss of high end content either.
I think it is wrong to believe that a cartridge will wear out in such a short period of time as 2-4 years.
If handled properly, it should last longer.
You don't suppose the people who sell cartridges might have something to do with this type of audio mind set?
This cartridge I might add has seen service first on a LP12 with a FR12 arm, then an Oracle Delphi with EMT 11 arm,this is a span of 7 yearsof constant use before cd play.
Then it sat in it's box for the next dozen or more years until on a whim I tried it out on a VPI Scout.
I had been into some Grados and forgot why I stopped using the FR.
The best that the cartridge has ever sounded is now on a Rega P9 with the 1000 arm.
Even old scratched lps have less noise than when the cartridge was on the Scout.
I was looking at buying one of the newer mc, but that's not going to happen until this one bites the dust.
So,not all cartridges degenerate over time in my experience.
Maybe the FR's were just well built back in the 70's.
Maybe that's why they went out of business.
I wonder if the Shelter's will hold up like the FR's did.
Same designer.
While I appreciate all the above answers, I am still left confused as to how to recognize the onset of cartridge failure. I agree that if the suspension fails then the results will be probably obvious. However, what are the symtoms of failure of the diamond tip? It seems a little strange to have to remove the cartridge every so often and check the diamond under a microspcope. Assuming that wear is evident under the scope, how long has this been accruing and how much damage has already been done to the record.
If one could recognize diamond wear when it begins and knows the symtoms, it seems to me you could minimize or prohibit record wear.
Diamonds wear very slowly! By the time a diamond would have any significant wear, you would have noticed mistracking *long* before!

Record wear is primarily caused by mistracking- but rarely by a worn stylus! Far more common issues are poor tone arm setup and hardware that is really not up to the task. It is also not a good idea to play an LP more than once in 24 hours, so as to allow for the vinyl to rebound. If you think about it, the amount of pressure that a needle exerts on the LP is prodigious- once you work it out to weight per square inch.
Stylus wear or deterioration of the rubber suspension parts will be most evident from tracking problems. If you hear the music breaking up or sounding sibilant where the sound was clean before, some kind of wear or deterioration may be manifesting itself. A test record with music passages with increasingly higher modulation levels (loudness) are helpful, assuming you can recall how well the cartridge performed on these tests when new. Loud passages, with a lot of high frequency content, particularly toward the inner grooves of the record are the most difficult to track and should show up incipient problems first.

Most microscopic examinations can only detect really gross damage/wear. I've had cartridges examined that were obviously going bad that showed absolutely no wear even when examined under the proper kinds of stereoscopes. The only pictures I've seen that clearly showed subtle wear were those made by scanning electron microscopes and no shop would have access to that kind of gear.

I would go with what I hear to make the call as to when the stylus needs to be replaced.