Martyn
Supporting Sponsor, Overland Certified OC0018
How often should the Max Coupler be greased?
That depends on how often it's used. I'd say give it a pump of grease every month it's in regular use, make sure it's full before you are storing it.
If you do water crossings during a trip, when you get home, take the coupler off empty any water out and make sure it's full of grease. Keeping it lubed and keeping the water out is the goal.