RE: Powder Longevity???
Pellet boxes get air-exposed to a much greater extent than jug powder. Normally jug powder users have either a screw-on pour top with a snap-on cap (or) the user generallly loads a powder flask or two at home & leaves the jug at home.
All the pellets become somewhat exposed when opening the box. Taking the entire box of pellets is very common in my neck of the gun ranges around me.The center hole on pellets draws air too. So a percentage of pellets feel the wrath of air on the outside of the pelletand inside where the hole is.
My state of Michigan is loaded with an overall high humidity index. So shortened-life with pellets can be expected here. In more stable temperature-climateswith overall less humidity indexes, longer pellet life can be expected.