How to determine wear on a stylus?


Over the years I've accumulated several cartridges and would like to determine which have styluses that are still in good shape. I suppose a microscope would be the best way to examine them; any recommendations as to type and power? Or any other methods of determining wear on a stylus?
nedmast
RadioShack has a small pocket scope that works well. It is lighted and you can actually see the stylus (if you can FIND it at 100x!!!)
I search for the cantilever and then move up slowly.