Re: How often do you grease your trailer?
After the first five miles! By that time if the bearings have rusted significantly the hub will heat up. This will save looking out your rear view mirror and seeing smoke come from your trailer hub. It will also give you a chance to find out that you may not have latched the coupler, that you may have a chain dragging, or very realistically, that the binders need tightening as the load settles in to the trailer.
We all overlook things occasionally. Most of the time we get by due to God looking out for us and others, but why push the point?
I'm an old fart. My pee breaks are getting more frequent

, but a few years ago every two hours was a DOT reg and forced me to stop and check. That is not a bad schedule to keep. Tires on a hot day can surprise you. A quick check that can tell you to slow down 5 MPH to keep a blowout from happening is worth the check. Keeping a check on your equipment and load is a good thing.
Happy trailering!