K Charles wrote:
Pack the wheel bearings in your TT every time you pack them in your truck or car, or when you replace the brakes.
Most vehicles have sealed bearings any more. And my Toyotas routinely run over 100K miles on the original brakes. Those are not good guidelines for RVs!
Trailer Life website recommends annually or every 10K miles, whichever comes first. Grease also breaks down on stored trailers, from evaporation of the volatiles and oxidation from air.
This is a good article from Family Handyman, which recommends every 20K miles, or annually.