depending on the amount of lift you need to watch the following

CV joint angle - jack your rig up off the ground and turn the front wheels and feel if there is any binding or clicking. while it may only happen at full droop, it will begin to wear with regular road milage as the suspension travels.

Ball joints - the arms i took off jon's rig were completely shot, the threaded part of the ball joint was just dangling there, completely blown out

tire wear - watch for cupping, feathering & other unever wear patterns, make sure you have it aligned after you install the lift

suspension bushings - keep an eye on them and make sure the lift kit isn't binding the suspension somehow and causing premature wear, this is to include shock bushings... again, on jon's rig the aftermarket shocks were not correct and were wobbling around in there.