"The rule of thumb for the old backpacking was that the weight of your pack should equal the weight of yourself and the kitchen range combined. Just a casual glance at the full pack sitting on the floor could give you a double hernia and fuse four vertebrae. After carrying the pack all day, you had to remember to tie one leg to a tree before you dropped it. Otherwise you would float off into space. The pack eliminated the need for any special kind of ground-gripping shoes, because your feet would sink a foot and a half into hard-packed earth, two inches into solid rock."