First off, according to the feds you are only allowed to have so many primers (black powder and other stuff is also included) on hand. I know, nobody listened to those jerk offs, least of all me.
I have and use primers that were manufactured in the 50's threw the 80's, that work just as well as those I purchased a couple years ago, now it is unknown whether or not the primer manufacturers have found a way of giving primers a shelf life or not, I suspect not, but don't know. Primers will keep very well if you use a little care in their storage, keep them in the original boxes, (that should go without saying) keep them dry and avoid extreme changes in temperature. I know of primers that I purchased from yard sales that were manufactured in the late 50's and 60's that went bang 30 or more years later.
Having primers is important, they are what start the whole thing, but powder (unless it is black powder) is something else you need to consider. I have bought powder in 1# containers just like everyone else, but in the last 20 or so years that has only happened when I am working up a load , once I find what is to be used, it is all purchased in as large a container as possible. (Maybe more than 1 container, that depends on the size and how much storage I have at the time.)
Bullets are easy, jacketed bullets are harder to store, you want to shoot them up all the time. Get a bullet mould for the guns you own and cast bullets for general shooting and save the jacketed for hunting and carrying. Stash away a couple thousand jacketed if that be your desire, but cast lead will work just as well if you take the time to learn the process.
Black powder can be made, and according to the state I reside in, I am only allowed to have a very few pounds on hand, I can't say I pay much attention to that law or any of the others the great know it all government entities have concocted to hamper my rights to do what I want when it comes to guns and related. I have accumulated enough components to manufacture a couple hundred pounds of black powder, that doesn't seem to be regulated to much, but does require dry storage and the time to make it. For those who haven't tried it, black powder works great in straight wall and some bottle neck cases, it does require a little different technique, and is a mess to clean up after, but it is a lot of fun to shoot, and keeps you shooting when others are trying to find smokeless powder.
Ray