What happens when the stylus tip wears out on a $12,000 cartridge?

mulveling, Re your comment on why one cannot rebuild an MC, wouldn't there have to be an air gap between the moving coil and the magnet structures?  Can't be hard wired from stylus to output, I don't think.

@lewm sure the magnet & pole pieces of an MC generally sit outside of things, but the rest of it is hard connected: stylus > cantilever > joint pipe > armature / coils > lead outs.

Where does one choose to create the "break", and how does that affect moving mass, tolerances, field-replacement difficulty, and replacement costs?

@elliottbnewcombjr I highly doubt, lets say, a denon dl 103 with a spherical/conical stylus is going to be considered worn out or near worn out at 150 hours. 
 

The Denon 103 is also a nude conical, which puts it a significant cut above the typical (crappy) bonded conical. 

I’m no cartridge expert.... Is it even possible to build a MC cartridge with a removable stylus like MM’s? I’m guessing not or there would be plenty out there. I recentlu learned that early Ortofon Concordes were MC. Who knew

Anything's possible, but practicality is another matter. There's no natural air gap to serve as an easy separation point like with MM or MI. An MC is literally hardwired from stylus tip to lead outs - where every micrometer is incredibly delicate. You could create separation ability with custom contacts, but where? Anywhere before the coil is too delicate and would add too much moving mass, negating the performance of an MC. After the coil, and what's the point? You're replacing the most expensive parts of the cartridge right there, so economically it's not viable, and probably sacrificing some alignment tolerances too. 

It varies by manufacturer. Several offer a "full rebuild" for ~ 50% of MSRP, whereby you receive (after several weeks) a brand new cartridge in the old body. E.g. Koetsu, Ortofon. I like this option, but manufacturers dependent on a single ageing master (like Koetsu) mean it cannot be counted on for the long run (the Koetsu master passed away last year - RIP Fumihiko). I used the Koetsu option a few times; they really are good as new. Note MSRP can be relative to the distributor network you send it into! Ortofon handles these cases direct, which is much better IMO. If you can afford $12K one time, you can afford a $6K refresh every few years (don't use it for background music lol).

Some offer only "trade in" value to a new cartridge which is often paltry (e.g. 25%). I do not like these options. Benz Micro offered generous trade in allowances in the 2000s, but took those away when they couldn’t keep up with demand.

And then you always have the 3rd party retip / rebuild option. Retip is only possible when the coils, cantilever, and suspension are still intact. Both options here usually cost FAR less than the above options. None of the cartridge manufacturers make their own styli (and very few their own cantilevers), so it is often possible to retain much of the original design intention this way.

I definitely should have mentioned Van den Hul and SoundSmith offer excellent rebuild rates on their own cartridges! Much lower than 50%. It’s a huge advantage. I’ve really been enjoying some Van den Huls lately, and want to try SoundSmith too.

One of the problems with a worn stylus is the fact that it is now damaging your records. This can be something that is initially not that noticeable, until such time as you replace the cartridge or stylus and hear the groove damage!

@daveyf Is there any research or hard data around this topic? I find it hard to believe there would be NO audible cues for such a poorly conditioned stylus, especially on inner grooves, and especially if you have a "fresh" cartridge to compare (many of us here have several). I had an ancient Koetsu Onyx that sounded like magic on outer and middle grooves, but a mild overlay of grungy haze always emerged past those middle grooves. It could’ve been stylus wear, or suspension - I suspect the stylus. Anyways, I didn’t play it too much before rebuild, but the records I did play seem fine.

My impression of vinyl is that it’s quite resilient, and I prefer to avoid paranoia rabbit-holes on this issue. Sure, you can damage it - usually manifesting as lots of noise. I have some of those records in my collection, complements of prior owners. Many of these records still sound surprisingly good, other than the noise (loud ones, like Blue Oyster Cult and Metallica).

There’s a video on YouTube by vwestlife where he starts with a clean sounding record and plays the 1st track repeatedly with progressively insane VTF. IIRC he ends up at 30g VTF! (yes the suspension bottomed out so maybe not a full 30g). The record gets noisy, but honestly I was impressed how well vinyl held up to abject abuse. You read some of these forums, and they would make you think the grooves should have been rendered completely smooth past 10g VTF.