Yes you should still take your wheel bearings apart, clean, inspect, replace as needed and repack at that time.
even with the zerks, moisture still creeps into the bearing cavity, and works its magic on the surfaces of the rollers and races, that and the fact that most every trailer manufacture builds products with componants purchased on the bid processes, and bear in mind not all bearings are created equal, the hardening process can be shortened or cheapened up, which affects how deep the hardening runs on the product, and once the pitting/caviataing process gets thru the harnened metal, the flaking starts and it does not take long to run a bearing out.
being an ASE tech/service manager i have seen this first hand in the trucking business, and being the tournament director for the SD BASS federation and running the team for many years, i have repaired wheel bearings many times on those trips, it takes a short time to ruin the axle, and just not work the expense and down time it involves, our rec time is always too short on a good day.
