If you know the original form of the stylus; conical, elliptical, fine line etc. you can check for major wear with as little 30x magnification. A good jewelers lupe or a pocket Mag/tele would be up to this.
For a closer look you need more magnification, for deciding if the stylus is starting down the road of retip/replacement.
We used to use a 300x scope for this but they are expensive!
1) find a friendly analogue dealer that still offers this service
2) buy a normal microscope, remove the stage and use something like "helping hands" to hold the subject, you may also need to rig something for sufficient light.
Personally, (and unless you have an uber price-tastic cartridge) if it sounds OK it probably is. If not, check all your adjustments again before anything else.
Fully Modded Pssst ! Got any spare capacitors ?