The key with wheels is not the spoke count, but how well the wheel is tensioned, if the spoke tension is too low it will break spokes, even if there are 400 spokes on the wheel. One of the things you want then is a spoke tension meter and a rim where the maximum spoke tension is published, you tension all spokes to that level and then true by loosening so that when your done you have the highest tension possible in that wheel. As for the hub, most hubs are replaced not because they need to be, but because a pre-built machine laced wheel is so cheap that by the time you buy rim and spokes it cost's as much of not more then a pre-built wheel laced in China or some other far off land. There is no reason a hub can't run 100,000 miles, if properly maintained.