Bearing failure

[brycesteiner]

Why does bearing seem to fail on RV/trailers so much more often than automobiles?

My idea was because they just sit outside most of the year, probably drawing in moisture and condensation and then the heat vapor expands when they are finally used and the grease doesn't do much since it has mixed with the water.

My dad was just driving from northern Indiana down to Florida pulling their 2016 27' trailer (6600lb) and he repacked the bearing last year and didn't think he needed to do it again since it was only about 6000 miles ago. Just before he got to Indy he had one catch on fire. It toasted the whole inside and they had to get a new hub. It took hours to beat the old bearing out as it was nearly welded in. Ickes said it didn't need a new axle. Luckily there was no damage to the trailer itself. The guys there inspected the rest of the bearings and then sent them on their way.
They got in Florida and about an hour from the campground near Orlando (or somewhere around there) they had another bearing go out. This time it caught quicker and was only smoking.

Both times delayed them hours.

This is not something I want to go through on the montana. I know I'm only going to Kentucky with it and them leaving it there, but I still don't want this to happen.