When we were researching a new RV a few years ago I did read post with members that didn’t like the Nev-R-Lube the most common thing I heard was Chinese bearings and that it can take a week to 10 days to get parts. At the time I did ask if there were any positive comments and did get a number of good comments. I contacted the manufacture and they told me they had a 5 year 100,000 mile guarantee that sounded good and they had a new bearing supplier. We put anywhere between 8,000 to 12,000 miles a year on our trailer, last year was around 10,000 miles. In three years I estimate that we have around 30,000 on it and so far not any problems.
On our last fiver we re-packed the bearings every year and didn’t have any problems with them either, had to replace the shackles but not the bearings.
So far we’ve had good luck not any problems, I have had the trailer a lined and also the tires balanced, not sure if that has anything to do with it. Again not sure if it helps or not but we use an air hitch and MOR/ryde Independent Suspension. We only added these things because we’re retired and like to move around.