If you have the EZ Lube axles; pump fresh grease through the bearing until the old grease is flushed out every time you take it out, I believe you can extend the bearing dis-assembly and repack for 3 years. I have NO data to back this up.
The manual says to remove and inspect annually. I think it is overly conservative, but so far so good (will do mine this summer for the first time).
I am taking the camper to FL this winter (again) and if I lose a bearing I will have a lot of egg on my face for sure. Time will tell.