I wholly agree with Glenn's advice. I went from a 2 lb. pack to an Atmos and all my problems went away. Fit is essential, but the Atmos suspension carries if it's not there. I've used it as a daypack, and it carries lighter than a 1 lb. pack. It may become a weight liability if your pack weight is always under 20 lbs., though. Mine has certainly trended far downward over the decades, but, I still have to carry water into dry camps or multi-days of food on occasion.