Someone named Henk apparently studied this in detail, with microscopes, and came up with the following. Sadly, the original study/notes link doesn't work, but his notes were posted elsewhere: Life of a Diamond Stylus An ordinary circular needle has a life of approximately 600 hours . An elliptical 1000 hours , a shibata 1500 hours and 2000 hours fine line. Micro - Ridge has 4,000 hours, and Jan Allaerts makes up to 20,000 hours. So, as follows; (please read as "life-expectancy up to") Round stylus; 660 hrs Elliptical; 1,000 hrs Shibata; 1,500 hrs Fine line; 2,000 hrs Micro-ridge; 4,000 hrs Jan Allaerts; can be up to 20,000 hrs Being an old fart has its advantages because I can remember little info-bits from my early days in audio. Back in the late 50s/early 60s CBS did some destruct tests on styli and vinyl. They played discs for 500 hours, regularly cleaning the disc and the stylus and no disc was played more than twice a day. Their tests were on Shure M44 E types of cartridges at 2.5 grams and Stanton 500E cartridges and some others of similar ilk. At 100x [optical power] inspection, there was some wear on both the styli and the discs, with the worst wear showing up on discs that had recycled vinyl in them. Also since 45s were being pushed by RCA who competed with CBS, CBS enjoyed showing that 45s created more stylus wear than 33s (45s usually had much more recycled vinyl in them because returned 45s were regularly crushed, since many were "new" returns from record stores for items that didn't sell. RCA incorrectly assumed that new 45s could be crushed up because the vinyl hadn't be contaminated much by cigarette smoke, dirt, etc. In fact, simply pressing the vinyl "donut" was enough to make the vinyl brittle and hard to melt again. At 1000 hours all the styli showed substantial wear. They went from being small wedges that fitted "across" the groove and easily filled the high frequency spaces allowing them to "track" easily, to wedges that had "turned" sideways to the groove and whose sharp edges could easily slice off the high frequency "bumps". With discs containing 45 minutes of sound, the real point of these tests was to find out if a certain production run of discs had a much shorter lifespan than the general average. Testing styli and record wear was secondary. But the idea we should take away is that disc deterioration is so gradual that we will NEVER hear it happening. If you can actually see stylus wear with a 10x or 20x loupe, then you are certainly damaging your discs. The fact that a new stylus doesn't sound any different, means that the damage has reduced the highs forever, no matter what stylus you use now. I use a 100x-200x stylus check. For me the key is to protect the vinyl, because that can never be replaced. The stylus can be replaced easily. Sometimes I can use a slightly worn stylus for really damaged records or even 78s, depending on how the diamond has worn down, but the first time I see that a stylus is no longer properly shaped, it has become a hazard to my precious vinyl. I've don't this testing using a 100x stereo microscope for many years. I've noticed that some manufacturers use quality diamond that are unflawed, and straight with the grain, and mounted nude. While others use diamonds with any kind of "salt and pepper" inclusions, mounted in any direction on a bushing. Some manufacturers use high pressure plastic coatings to prolong stylus life and others don't. Worst of all, sometimes a company with great diamonds and mounting will cheapen a product and if you don't check it right out of the box, it may not have any life in it at all. Usually the better diamonds, with the best polish, and the best glues and coatings last much longer than those without. Light tracking styli have been good in some slight ways, but really bad in others. With higher compliance, there is the likelihood that stylus life and disc damage will be improved (in my testing about 5%-10% under the best of circumstances. But even the slightest amount of reduced tracking force that allows the stylus tip to lose contact with the vinyl surface (even inaudibly) allows the sharp diamond stylus to crash back to the disc surface, usually cutting a tiny notch where it remade contact. On perfectly smooth disc grooves, or cut with a single frequency, when the stylus breaks contact with the groove due to dirt or overmodulation, the stylus is resonating and the wave has not been fully damped out so it may remake contact with a "soft landing". But since real music has constantly changing groove modulations, breaking contact for even an instant will often send the stylus tip back towards the groove modulations in a direction that is perpendicular to the vinyl and with a very high force depending on tip mass. This tendency to bounce on and off of the vinyl itself is extremely damaging to vinyl. Better to always track at the top limit of the tracking force to keep the stylus firmly planted on the vinyl surface than to risk the stylus ever leaving contact and bouncing around on the disc surface. Additionally recent developments in stylus design like the Ortofon Replicant, Shure MR, AT ML, Garrot MicroTracer, Stanton Stereohedron, Gyger and VdH full contact multifacet styli, allow the disc to be played properly in spite of some stylus wear, because the worn stylus tip has exactly the same shape as the new stylus tip, until it is catastrophically worn. These styli can play a disc for 1200 or 1400 hours and show no problematic vinyl damage in spite of substantial wear on the stylus. Unfortunately spherical and elliptical styli may not have even half that much stylus life before they start creating substantial (unfixable by a stylus replacement) damage to vinyl. Since the range of stylus lives is so different, it is best to err on the side of safety and dump any stylus with any visible wear, unless you have a really powerful inspection microscope that you use often. I know that Denon tried very hard to use the best diamonds and their spherical styli seem to last much longer than any other spherical styli. Polishing expertise and quality diamonds seem like the keys to Denon's success here. Decca also uses great diamonds and older Ortofon diamonds were incredibly good as well. But most spherical diamonds aren't in that class, and will show wear at 500-600 hours and most ellipticals will show substantial wear at 800-900 hours. More than that is risking vinyl (which can never be fixed and often cannot be replaced), against styli which can always be replaced if you by cartridges with available or spare styli, or you get your MC cartridges retipped at the first sign of wear. .