they both wear out..no giv'n time frame..it's always best to keep them tight at all times...as too when and which one goes bad..no telling...your best bet is to see which one is worse..and the cheapest to replace..more than likely the hub splines are the worst..hard to tell without seeing them. just see which one is stripped the worst..then decide cost wise which one you can afford. longer hubs is probally better..sinse you don't have anything that can turn on the axle if your hub gets loose..i would go with longer hubs if it were me.I have a little play in my axle hubs. which is more common, the spline in the hubs to wear out, or the spline on the axle? which should I replace?
Plus i've seen new hubs that are a inch longer, is this better than spacers?
Thanks