The recent posts regarding prepared-ness in the mountains brought this to mind:

http://www.rei.com/learn/expert-advice/ten-essentials.html

How many of you carry what are regarded as the essentials, and if not, why not? If you carry the "ten", what extras do you bring?

Even on a little day-hike, I carry the "ten", my Enzo Trapper bush-craft knife and flint, and adequate food, so that I can survive at least one night in the event I have an accident.