When is the best time to check and add grease?

The hub is almost always subject to water infiltration when at operating temperature (warm) and placed in ambient water while launching your boat. This will most likely happen while launching after an over-the-road tow. The ambient water will quickly cool the grease reservoir and cause the hot grease to reduce. Water infiltration by siphon will ensue. Add grease to displace water on all but bearing buddy equipped models. If towing long distance, monitor hub condition at each rest or gasoline stop. Add grease as necessary.