Is your bag as big as mine? Depends on the scenario, but basic needs would be, change of clothes, socks, wet weather gear, climate oriented gear (coats, gloves etc..) sleeping bag or system, form of portable shelter, water, food, first aid essentials, fire starting tools, rope or 550 cord, duct tape, radio, ammo/magazines. List could go on and on, but to keep it stupid simple, food, shelter, clothes, way to defend yourself/hunt, communication and first aid. Once again, depending upon scenario, you might have to hump that shit on your back for long distances.