How do you know when to replace the stylist?

Thanks Tvad...VERY Helpful

1. When you have enough $$$ in bank account.
2. When you are no longer satisfied with the sound produced by the current cartridge.
3. When hear your friend (or anybody) bragging about a new cartridge and how good it is.
4. After finding out the needle is worn out (inspecting with at least 30x magnifier glass or microscope).
5. When you have just found out a real deal going on ebay (or agon) and would not want to miss the deal.

Actually, those were most of the reasons why I replaced the cartridge/needle. 5-3-1-2-4 is the order (the most frequent/compelling to the least frequent/compelling reason) that have occurred to me. I guess I have bought about 15 cartridges over the last 10 years, from Grado ($30) to Clearaudio ($250).

"When [you] hear your friend (or anybody) bragging about a new cartridge and how good it is."

Hee-hee...My system can beat up your system :b

Usually it starts out with a slight degradation in cymbals, or some sybilance in sounds, then outright distortion with various types of music. It will appear at first as if the needle is dirty and trying to clean it will not change the sound. Try to imagine your needle full of sludge and worn down trying to play a groove,,,that will sound bad.
Ciao,
Audioquest4life

I second what audioquest 4life says. I am in the process of replacing my current cartridge. I started loosing detail in the high frequencies and certain passages started sounding more sibilant, and some music would just totally distort to where I couldn't listen. Basically the cartridge couldn't track well any more. It sounded like bad inner groove distortion.