I've found that before I can declare seeds "duds", I need to re-try them as transplants. Especially given that after one failure, I'm usually in rescue mode for the remainder. (I almost always set some seed aside in case of failure.) A pole wax bean last grown in 2015 ("Blue Blockeye") had 0% germination when direct seeded last year, but had 97% germination in pots.
Then again, soybeans which I had tested at 30-50% before planting had VERY poor germination this year when direct seeded - in 2 cases, only a single plant survived! The seed corn fly has proven to cause
apparent "duds" even from good seeds. So it appears that going forward, I need to start
all legumes in the rural plot from transplants.
Soybeans & sweet peppers seem to have a shorter seed life than most vegetables, those are the only two species where I've had a variety die completely in storage. Other seeds that I once
thought to have poor storage life (such as bitter melon, okra, and limas) turned out to have
much greater longevity when I saved seed & had total control of storage conditions - hence my previous comments about commercial seed mishandling.