The slogan "Leave no trace" (LNT) summarizes a trend among hikers to address concerns about conservation of the ecosystems and scenery that often motivate hikes. An organization of the same name promotes LNT practices in cooperation with the NOLS and the AMC.
One simple and fundamental aspect of LNT is "If you can carry it in, you can carry it back out"; a particularly blatant target of this principle is the popular disposable plastic bottle of water, which weighs a pound or so, and has a volume that challenges many pockets. Once empty, with its top left loose, it is a five-second project to convert it into a negligible weight occupying a back pocket, instead of a slow-to-decay eyesore