I have found that wheel bearings are the least troublesome of trailer problems.
I pack the bearings on my sail boat trailer yearly as they're underwater at times.
The last time I packed the bearings on my ATV trailer was 5 years ago.
I did the bearings on my new to me 86 Lil Bigfoot
when I bought it last fall
It will probably be 3 or 4 years before I need to pack them again.
I'm 71 years old and have been towing things for 50 years and have never lost a wheel bearing.
I bring this up because I think some people new to trailering may be a little to concerned about bearings and it will spoil their enjoyment.
If the bearing cup is cool or only slightly warm you have nothing to be concerned about.
If you are not mechanically inclined DON"T do it yourself.
If it's not done correctly you will have a major expense on your hands.