Lots of rattling noise compared to when your filter was new.
Usually it's the shaft the impeller sits on that wears before the impeller - the magnet isn't contacting anything in a well-made filter. Of course, the internal cylnider of the impeller that the shaft inserts in will wear also as it is spins on the metal or ceramic shaft.
I don't think the magnet gets demagnetized; and I have run a fluval 203 for over 10 years without replacing the impeller OR the shaft.
...I guess you could say I'm past due to get the shaft.
