Wheel Bearings (4WD)

I thought I saw something in the maintenance for the 4WD Tucson that said the wheel bearings need to be repacked, but I can't recall where I saw it. Does anyone know how often the wheel bearings need to be repacked, which bearings need to be repacked (front, rear, inner, outer, etc.)? If you could also quote your source, I'd appreciate it.
 
Adam

Bearings and seals should be cleaned and repacked when taken apart, this gets any contamination off the pieces before you put them back in..That is the way that I do things myself...
 
WheelBroker1