I put about 7-10K miles on my FW every year. Before we head out on our summer journey, I remove each wheel and hub, inspect the brakes, including linings, magnets, wiring and drums. Then, I remove the grease seals, clean and inspect the bearings and repack the bearings with new grease. I follow this up with new double lip grease seals and then install the hub with the proper bearing pre-load. When it's all installed, I finish off with a brake adjustment.
There is NO way to understand what is physically going on behind the drum unless you (or your mechanic) physically inspect it. Yes, you can inject grease into the hub with the EZ lube, but that is a short cut I refuse to take. I want to know the condition of the critical components that are inside.
Jim