Real world life expectancy of a high end cartridge?

I'm going to be the creep again. Stylast like Last is nothing but freon. A great solvent for non polar substances like oil but nothing more. You can prove this to yourself. Put a drop on a glass slide and let it evaporate. Do it again in the same spot. Do it a thousand times and what you will be left with is absolutely nothing on the slide. Zip. Zero. Nada. If there is a positive gain it is just from keeping your stylus clean. But, you can get freon a lot cheaper. We are easy targets for crap like this. By all means keep your stylus clean. The best way to determine stylus life is looking for wear under magnification. Everything else is just guessing.
Click away Elizabeth. 

Mike

Moreover to benjie’s comment, how does the suggested experiment “prove” that stylast is Freon? There are any number of liquids that evaporate without leaving a residue.

 I haven’t used stylast for several years. I was skeptical of the idea to use magic eraser. Then I used a microscope to look at Styli before and after a careful magic eraser treatment. That experiment converted me to magic eraser for cleaning my stylus. No liquids. It’s quite remarkable.
I have no beef with stylast. I certainly never had a problem with it. But where there is smoke, there is sometimes fire.  So I prefer not to take a chance.

Freon boils at minus 41 degrees Fahrenheit. Freon at normal room temp is a gas. But that's probably just the cheap freon everyone else uses. Obviously, Stylast uses the really good room temperature liquid freon. 

It can be kept in the liquid phase when under high pressure, but I agree with your basic point as regards Stylast.