I would recommend only loading as many as you are going to use in the next several months.
I would suggest that you buy a couple of powders, ones that are not temp sensative, and work up a good load for your AR.
Then get the components and store them in that form.
The reason is that there are many threads of guys that change their pet loads and then are stuck with the choice of just trying to use those thousands of rounds of what ever you are not using, or, pulling the bullets and reloading them.
Personally buying a pound of powder is still a good thing. I know that i could turn around and sell any of the ones i have bought for $20 very easily, same goes for all the other components. Loaded bullets are a different deal.
So, i would get the stuff to load what you like, but don't load them, just have it so that you can load them at your lesure.