I have a small trailer as I have a pretty small boat. I bought the trailer 5 years ago. It has permanently sealed bearings that require no maintenance. So far no problem. I'm starting to wonder what would happen though if I had a breakdown while on a trip. Especially a little concerned about being out in the middle of no where while on my annual Canada trip and having a problem. I'm thinking I should probably get a hub assembly to have on me as insurance. Just wondering if anyone else here has these bearings and your experience.