I'm with Jokerman on this one.
Pick up a set of grease seals, grease, lots of paper towels. Disassemble the hubs, clean the bearings. Look closely at the rollers & races, if they look OK, they are OK. I have 200,000 miles on my pickup's front wheel bearings: they will last if you keep them lubed. Repack the bearings if they look OK (I like to load the hub with lots of grease too) install new grease seals in the hub, shoot some grease in on occasion over the course of the next 10 years. No sense buying new when there is nothing wrong with the old. If you're concerned, carry an extra spindle and loaded hub (so long as your spindles are bolt on, not weld on), they're not bad to swap out if one locks up.