Here's a tip - if you can run a fingernail around a cup (or race, whatever) and feel any nicks, time to replace the cup (or race, whatever). I guess I'm just funny when it comes to wheel bearings and seals on trailers. I check them at least once a year, carry grease and tools with me, check the hubs for signs of heat every time I stop, and am just paranoid about it. I travel the thruway here everyday and see trailers pulled over all the time. I bet they're not camping!
NAPA has about every size dust cover ever made, plus complete bearing/seal kits for every axle
you can imagine, and some ya can't!