You will start to hear mis-tracking, "harshness" and sibilance in the high frequencies, especially on the inner grooves.   With Dynavector's unique micro-ridge type stylii (fitted to all models from DV-20X and up in 2015 and ALL models after 2018) there will be NO deterioration in sound until right at the very end of the stylus' life.
As always, remember to keep your stylus and LP's clean to extend their life.