Depends, my wildcat formed brass gets the full treatment and I can get 15-20 loadings if I anneal a couple of times.
Common stuff I get 6-8 depending on chambering and quality of brass.
Properly stored, lose powder and loaded ammo could both last longer than the owner lives. I prefer stored as loaded.
I have loaded rounds for my 45 ACP that were assembled in 1937, they shoot just fine.