Need Advice on Checking Stylus

Would appreciate some advice on how to check the condition of a stylus. My primary cartridges are the Soundsmith Zephyr and the Lyra Delos. I just bought a vintage pocket stylus magnifer (50x) for a couple of bucks. Ok, so what now?? I assume I'll need a good light source. Is a penlight flashlight enough, or shouold I buy something else?

Ok, when I get the proper light source and my stylus magnifer is delivered, what am I looking for? How can I estimate sylus condition and wear?? As I recall, the Zephyr has an elliptical stylus. The Delos is a micro-ridge contact line -- I think.

Thanks.