Real world life expectancy of a high end cartridge?

When I was in high school I worked for DBx in Waltham. I constructed the chassis for 32 channel noise reduction units. We had a large bath that cleaned the flux off of circuit boards. We filled it every morning with a Freon. I lived with that smell for a year. Most Chlorofluorocarbons smell pretty much alike. I did not say brake cleaner was Freon. It is another Chlorofluorocarbon that smells pretty much like a Freon. Last is a Freon and nothing else. Its your money. 
Neither Iso propyl or Ethyl alcohols will attack the adhesive used to fix styli in place. You can use Ethyl (denatured) alcohol to clean up uncured epoxy but once the epoxy has cured the alcohols won't touch it. 

Pleased to find out that when my Dynavector DV 20X2L cantilever finally died after 3000 hours and alcohol induced fumbling that Dynavector dealer gave me a good discount on a replacement trade in. Not sure if this is WW?

I love the way people argue rather than taking 5 minutes to check the facts readily available on line, e.g. Google for Walter Davies's patent on Stylast ...

https://patents.google.com/patent/US5389281A/en

As a funny coincidence the patents expires today July 6th 2019. This is his only patent in his name in this field and is quite easy to read. It seems to describe the product he went on to sell in rather different terms to those used in prior replies here and reading it may add fuel to the fire.

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You can lead a horse to water but you cannot make it drink!.......