maybe im not understanding you. are you talking about locking the hubs and leaving them locked or just lock them when you need them? if you leave them locked all the time it will hurt mileage and wear things out in the front end over time. if want to replace them dont spent a couple hunred dollars a piece for factory locks. you can get a pair of warn, super winch, or mile marker locks for about half the cost of one factory lock. but you wont have th shift on the fly feature with those after market locks.