Pack in, pack out is one of the credos of wilderness activity; translated, it basically means that whatever you bring with you when you hike and camp should also be taken home as well. Many experienced campers achieve this by bringing along plastic garbage bags, which also can be used for such things as covering a backpack to keep it dry during a shower or storm.
Taking that idea further, garbage bags -- particularly the large, heavy-duty 55-gallon type -- are exceptionally useful in survival situations. Staying warm and dry is at the top of the list of priorities whenever you're exposed to the elements, particularly if you don't know how long it will be until you have access to shelter and heat. Cutting a hole in the top of a large trash bag and slipping your head through it instantly makes it a rain jacket and windbreaker. But that's just the beginning of the uses of a garbage sack. They can also be used as protection from the sun, or, if filled with leaves, as a pillow or mattress or simply as something to sit or lie on that will keep you from getting wet on the damp ground. Garbage bags can also be used to obtain essential drinking water. It can be filled with snow and left to melt, leaving a container full of H2O or deposited in a hole as a way to catch rainwater.
Read on to see why a watch has many more uses than just telling time.