Can't really camp if you don't have water. One from the archives by Brock Akers:
http://www.rokslide.com/2012-01-09-05-12-00/backpacking/290-high-country-hydration
Nope, just 1 bladder and water bottleGood article! So I have a 3L bladder and it sounds as if I drink 2 full bladders a day, I'd be fine. Does anyone carry an extra bladder with them for whatever reason?