Either a day hike or long expedition I always carry a lighter, firestarter, emergency blanket, emergency poncho, Mountain money (toilet paper), small shovel, water, water purifier, salty and/or high energy food, ducttape, whistle, compass, camara, knife, flashlight, piece of twine or rope, first aid kit with asprin and Benidril, and a small flask of Crown Royal. It's amazing that all this can fit into a small backpack or water bladder pouch, but when you need any or it you will always be happy.