The motor’s magnets can vibrate loose over time or fall off with a big slam. Several folks had to deal with this and they’ve generally come to the conclusion that “battle hardening” them is a good idea for preventing failure.
Battle hardening consists of filling the gaps between magnets with a NON METAL epoxy. I also covered my sensor board pcb inside the motor to prevent any shorts that could happen.
Here is a much better looking motor battle hardening by the wonderful @Andy87 :
@Lee_Wright made a great video as well:
But I found the milliput to be too thick to spread nicely. It was like a hard play dough and working time was short. Something a bit thinner would have made application and clean up nicer.