With proper lubrication, hubs with decent bearings last a very very long time. The cups and cones develop a polished ring, but that's not a sign that they're wearing out. If you ride with deteriorated grease, pits can develop; but that's not normal wear and tear. That's extreme, and an overhaul --or even a little oil dripped in-- would have prevented it.

If you're going to go to the effort of building a wheel, build it with a dynamo hub. And yes, anyone can build a wheel. Getting it radially true (round, that is) is not difficult; nor is lateral true, proper tension, etc. The skilled professional can do it quickly, while it may tax the novice's patience, but it's worth it.