I replaced my rear ones at 140,674 miles. You can hear them growl when they go
bad. It was the Rear right that was making noise, but I do both. They're relatively
easy to replace. I did the fronts at 149,337 miles, smoothed the ride considerably.
They were not making noise yet, but a little wobbly. When bearings wear to the
point where they wobble, it can warp the rotors gradually as you brake.
I did not have to take anything apart to do the rears. Just push the axles in so
the bolts clear. You may need some heat to separate the bearing from the socket.
Hammer the hub disc from the back, then front, then back, till you see it start to
come out of the socket. Then you can pry bar it out, or keep hammering back
and forth.
Optimally, you use this tool:
Bolt that to the hub, and hammer on it downward, then rotate it clockwise:
Turn 45 degrees, hammer <--
Turn 45 degrees, hammer ^
Turn 45 degrees, hammer -->
Turn 45 degrees, hammer down, and continue till it pops out.
I never used one, I was always able to hammer the hub from behind and
front repeatedly till it popped out.