Packing a sleeping bag for longer hikes is standard, but don't neglect to pack a sleeping pad as well. Sleeping bags alone don't offer protection against the cold hard ground under your tent. Pads can come in a variety of thicknesses. Almost all are designed to roll up and attach to your backpack. Since pads are generally waterproof, made of some synthetic material, you can also use sleeping pads in emergency situations. They make excellent flotation devices if you ever find yourself stuck in high water!