How do I know if cartridge replacement is needed?

I just recently purchaced a Sanyo turntable. I know very little about it.
Most vinyl sounds pretty decent on it, but occasionally there is a distortion in the higher frequencies of my music.
The table has a Grado cartidge on it now, I don't know when it was installed. Do I need a new cartidge?
No one could say from the information provided whether your Grado needs replacement.

- Have you checked the cartridge setup and alignment thoroughly, or had it checked by someone who knows how?

- How old is it? If it's more than ten years the suspension parts may have started to deteriorate just from age.

- How many hours on it? If it's more than 1,500 or 2,000 it's probably due for replacement.

BTW, Grado's are not famed for being the best HF trackers. Distorted highs, especially on inner grooves, is one of their frequently reported "features".
Dear Ben: Other than what Doug rightly posted: I don't know the quality performance of your Sanyo TT and I don't know the quality of its tonearm, maybe you could have a Grado problem but maybe not, I can't be sure with your info, maybe the tonearm is not a very good performer or it is not a good match with the Grado cartridge.

Anyway, why don't look to test the Grado on a friend system or in a local audio dealer and " see " what happen.

Regards and enjoy the music.