I've spent too many hours sitting in a blind, when nothing other than leaves moved, to not take something(s) with me to occupy my mind, which helps keep my mind off of the aches & pains I may be feeling by just sitting there so long. Since I rarely get all of the sleep I really need, simply sitting too still and watching/waiting will almost always find me falling asleep. Where I'm usually at in a blind, there is no cell phone signal, but my iPad will have plenty of books for me to be reading, or allow me to post some notes to myself about things I wish to not forget; sometimes even one earphone is used and some tunes are very quietly enjoyed while watching and still listening for game.
Sam