I just repacked mine for the first time at 30,000 miles and they were still in great condition, plenty of good grease and no sign of problems or any water intrusion. The manual says to regrease at 30,000 miles for Schedule 1 maintenance or at every 3,750 miles if you operate frequently in water. "Frequently" is pretty vague. What it boils down to is preventive maintenance. You can go by the maintenance outlined in the manual or ignore it and hope nothing goes wrong down the road.