bearing
If you have that magic 5-6000 miles I would say it is cheap insurance, because they dont go so well when the bearing quits...lived that.
Like all parts-- someone will respond that they have 2million miles on the stock bearing,(like that geek in snogoer with 10k on his rx1) but I would change it if you go anywhere besides the back yard.
For that matter - check all bearings in your skid as well.
Good luck, and do the snow dance or we will all be changing skid bearings from the mud holes.