I'll admit to taking shot shells apart for the components. The only component I save is the shot. It's for making 38 Spl and 357 Mag shotshells. I don't need a 25# bag of #7 shot; but taking a few shotshells apart gives me the shot I need for making the shotshells. It's a good way of trying different sized shot, without having to purchase pounds of it. Precision Reloading even makes a handy tool for breaking down the shells if you don't want to save the hulls.
Hull and wad is discarded, powder disposed of, and primer made inert.