Just like tools, spare parts can keep you from getting off the trail if you don’t have them. We almost always bring a couple of U-joints: one for our axleshafts and one for our driveshafts. We also almost always carry a spare see-through fuel filter, an assortment of fuses, cotter pins, and a tire repair kit. If your Jeep has lockers and big tires, you may want to bring spare axleshafts, spare driveshafts, yokes, and U-joint straps or U-bolts. Some even carry spare ball joints, an extra starter, an alternator, and so on. It’s good to be prepared, but don’t overdo it. Extra parts and tools get heavy fast.