With the camping season just kicking off I thought I'd share my experience in hopes that it might help someone else.
Our pod is just 2 years old with maybe 5k miles at most. I thought I'd repack the bearings before I took it out on the first trip of the year and it's a good thing I did. I was very surprised to find that water had made it into at least one of the bearings (I still have to do the other side).
The contamination was only on the outer bearing, so the cap must have failed. The inner bearing looked good. As you can see from the picture below it has obvious signs of rust and pitting.
Luckily my local NAPA had a kit with everything (bearings, races, cap & seals). I picked up a couple just in case the other side has the same issue.
So... if you think squirting a little grease through the zerk will make everything ready to go, think again. The grease itself showed no signs of contamination and both the washer and castle nut were fine. If I had just topped it off I never would have known. Make sure that you (or a trusted RV shop) take the bearings apart regularly and inspect and repack. I'll be doing this every year from now on.
I also discovered a few interesting things about the brakes that I'll share in another thread (after I take the pictures).