We have Easy Lube axles on our 2013 21. When we got it I disassembled the hubs, examined the brakes, and repacked the bearings. When I cleaned up the spindles it gave me a chance to closely examine how that feature works and to put some new clean grease in the easy lube voids, driving out the old grease. Then I cleaned everything up and reassembled with hand packed new grease. Then I did this again in 2018, 2019 and 2020 because we traveled a lot in those first three years. Since then with Covid I’ve grease every 8,000 to 11,000 miles. I’ve posted several times that I feel the examination gives me Peace of mind and I’m working on the trailer anyway rotating the tires, cleaning things up and checking the other systems so to me it’s just what I do.
I bought my first boat trailer when I was 15, got the wheel bearing lesson from my dad who was a European Theatre tanker in WWII and never looked back except to back in, and then not that often after I mastered the mirrors. I buy grease and parts from Midwest Wheel in Cedar Rapids, Iowa. Smart people on the counter, genuine Dexter dealers and speedy service. YMMV
Iowa Dave