like anything it is a maintenance thing for me...
i clean the ball and socket regularly
personally i think the dust in the grease problem to be a bit of a furphy as it's been my experience the lube is pushed to the edges and any dust gathers there, away from the wear zone.
i drive a few dirt roads and have never seen extra wear but i can see it could / would become an issue if you didnt do regular maintenance.
it makes for quieter driving as well in my experience.

