According to a Dexter engineer that I spoke to years ago, EZ Lube axles were developed for boat trailers that get immersed in water. It was a good way to push most of that water out until a proper disassembly and repack could be done on the bearings. It morphed into a marketing feature. Potential buyers think they're getting something fancy with that system. They don't. Perform regular maintenance on the axles like you would any other trailer. I pull my hubs and inspect when I get a new trailer, just to make sure the factory did it right. Don't have to do it again until its brake maintenance time.