With RV trailer wheels you don't even need to do this twice a year. This is my second trailer with EZLube axles. I only do them every couple of years. I had my last trailer for 10 years and when inspecting the bearings they were always in perfect condition and properly greased.
2013 Jayco Jayfeather X20 E, 2008 GMC Sierra 1500 Crew Cab Z71 SLE