How often do you check tracking force?

If you have your overhang and anti-skate set well you will wear our your cantilever assembly well before you wear our your stylus.
 

@thebrokenrecord I actually haven’t worn a cartridge out yet. I upgraded after couple of hundred hours a few times and didn’t give it a chance to wear out. But I was always under the impression that the stylus will wear out first. Interesting…

@markcasazza I apologize for taking so long to respond to your question.  My wife and I have been traveling from our home in FL to our home in NH.  Anyway, the first thing to know is that @thebrokenrecord is incorrect that the cantilever is likely to give out before the stylus is worn.  In fact, I have been checking stylus assemblies since working for a high end hi-fi shop in Seattle during my college years beginning in 1970 and I have not ever seen that happen.  With that said, I suppose it is possible, particularly if the cartridge had been stored in an environment that was deleterious to the elastomer that the cantilever is supported in.  So I will never say never.  Anyway, the way to check for stylus wear is to fix the stylus under the microscope so that the tip is facing up directly at the lens and you are looking down at the tip.  Then focus first on the tip to see if it is even.  As it wears there will usually be wear points on each side of the tip that can be discerned as shiny spots.  This will be easiest to see looking at a conical or an elliptical stylus.  Fine line and Shibata and similar more complex profiles are much more difficult to spot wear on.  This is because there is less surface area at the tip.  Proceed by looking down the sides of the stylus.  The better your microscope, the better the depth of field will be even at high magnification.  Over the years there as been much discussion and debate concerning the effects that a worn stylus might have on the vinyl groove.  In my opinion, shapes like Fine line, Shibata or similar, which have sharp edges when new with relatively large contact area with the vinyl wall tend to wear smooth and so as long as you replace them in a timely manner the potential to damage your vinyl should be minimal.  Conical in particular, but elliptical as well, tend to start out smooth, and importantly have relatively small contact area with the vinyl groove walls when new and tend to wear with sharp edges, which I believe are more likely to damage vinyl.  How often to check is a function of rate of use.  As a rough starting point, I recommend checking your stylus every 6 months. 

@billstevenson  Thank you for the details. I run a Shibata stylus on my primary turntable. In the garage it is the original that came with the Pioneer which is where I want to start with inspections. My microscope is an antique, but the eyepieces are all new. My depth of field is okay at lower powers, but pretty tight as I crank up the power. https://www.facebook.com/share/p/16m754VXHU/  

It is fun to use and perhaps this will be the first time I use it for serious work. My Shibata has about 300 hours on it with every record always cleaned prior to playing. Some not so great as it was before I had an ultrasonic cleaner, but at least with a SpinClean. I got the Pioneer used so it is anyone's guess the condition, but then again, it is in the garage. 

@billstevenson "I have been checking stylus assemblies since working for a high end hi-fi shop in Seattle during my college years beginning in 1970 and I have not ever seen that happen."

That's because the assembly doesn't look noticeably worse, but it sure sounds that way. So what I'm saying that changes that occur with the cantilever will have a bigger negative impact on the cartridge's sonic performance that the stylus wear that may or may not occur within the same timeframe.

@thebrokenrecord Like I already wrote, in my experience stylus wear precedes cantilever failure.  When I check a stylus the set up is always refreshed.  For years I used ordinary test records to verify performance.  Last summer I invested in AnalogMagik, which is far more sophisticated.  So I am learning more all the time.  Perhaps I will discover what you have described in the near future.