Only a small percentage of the millions of shooters across the country reload their own ammunition. Among those who do reload, not many cast or swage their own bullets. Comparatively speaking, folks who reload shotshells are few and far between. I’m one of the rare birds who fall into all three categories: loading metallic shells, casting/swaging my own projectiles, and loading shotgun shells.
In reloading, a number of factors bear on the accuracy and safety of your ammo. As you reuse your cases, they wear and stretch. At some point they will fail. All things that get used will, and cases are subject to various stresses that ultimately result in failure.