I have been intending to put this up for the last couple of weeks but issues at home delayed it, I hope it is of some use to some of you.
I have a Michel Cusis cartridge (a Benz Micro Wood S in a composite body) which has done about 700 hours. The cartridge is extremely good producing a very natural, neutral musical sound. However some months ago I began to become concerned that it might be nearing the end of its life as I noted that its sound had become a little dulled and was possibly loosing some detail. So I got some pennies together and purchased a Benz Micro LP-S, which is great.
As many say a modern stylus should be good for around 1500 hours I wanted to check the Cusis out, so I purchased a usb magnifying camera. After much fiddling about and practice I managed to get a good picture of the stylus at various angles and even though I regularly clean it with a recommended stylus carbon brush I could see it was filthy with what looked like a black coating on it. I went on to read several articles on the net and many confirmed my findings and advised very careful cleaning using a none alcoholic cleaning liquid. Several recommended using neat L'Art du Son on an ear bud lightly dampened with it, which I already had.
I supported the cartridge (off the arm) so that the stylus cantilever pointed downwards and very gently applied the ear bud to the stylus tip on the cantilever, I did this several times and examined the stylus with the usb magnifying camera, after about 3 goes. What I found was that the black gunge was VERY stubborn to remove. It took about 12 applications of the ear bud. Afterwards I could clearly see the side profile of the stylus and with the usb magnifying camera light shiny directly done on it the diamond actually shone and was no longer dull.
If you do this yourself be sure not to put any pressure on the stylus cantilever, just gently touch the stylus tip with the ear bud.
I popped the cartridge back, carefully set up the arm and immediately the difference was obvious, it now sounded like it had when nearly new, lots of detail, musical and not in the least bit dull. I will continue to use it and check regularly.
So this may well be worth considering with your stylus before you right it off, obviously I would recommend you be guided by what the manufacturer advises on likely stylus life playing clean good records. If you are not sure then I would get it examined with a microscope. It should be noted that different cuts of stylus profile do have a different life expectancy.
By the way all my records are meticulously cleaned before I play them, but as various articles say, microscopic dust and dirt will always get into the groove and with the heat generated from the stylus passing through the groove the black gunge will eventually build up on the stylus.