Yes, this I know <img src="/images/graemlins/laugh.gif" alt="" />... Growing up in VT I can remember carrying only 2 1L Nalgene bottles and an empty 2L dromedary bag the nights when hking the long trail... Today in AZ, I wouldn't dare do a similar trip without 2 x 3L hydration bladders and a Nalgene bottle <img src="/images/graemlins/laugh.gif" alt="" /> It was quite a paradigm shif for this Vermont Boy!