Are you sure you're not thinking of neutrons? They only last about fifteen minutes if you don't put them in a safe place. And don't be too hard on them; it's the glue. We didn't have much to work with back then.
Actually protons are pretty hardy little critters. I haven't had to get a replacement supply yet. By the way, that half-life calculation is the lower limit.
I know free neutrons don't last very long... but, did you not detect the irony of my post??