part of me just doesnt like the idea of ignoring bearing areas until they fail, and don't mind doing the infrequent maintenance--its just I don't know if its kosher to open up these things when officially we are discouraged from doing so.
As long as they turn smoothly without play, I'd leave them alone. Once they start to feel rumbly or gritty, though, you don't have much to lose as you'd be buying new bearings at that point anyway. Some folks use a dental pick to get in there and pry off the seals to avoid damage.
