First 5.56 2.23 brass does not vary much in volume between brands. There is a very good article on 223, with some very good tables (one shows case capacities), and don't miss the Sierra load guide free downloads:
http://www.accurateshooter.com/cartridge-guides/223rem/
I like Lake City because they seem to be consistent good quality and available inexpensively. I "could" pickup all the free 223 I want at the range, but that is not 1000 of any one brand, which are more or less identical.
The reason I sort by year is to keep my "lots" separate by where I got them, and to have an idea of what I have done with them. For example all of my LC year x1, x2, x3, I got from GIBRASS.com. If I need my best I get them from the box they came in. If they are already outside of that box, then I have loaded then about 2 times already, they are still good. One the other hand, years x7, x8, x9 I picked up at a range, and they look like they have been reloaded before: I used those for plinkers once, and they are scrap after next time. After being shot, they all go into a common cleaning process. I do not touch them anymore than possible until I sort them after tumbling when they are shiny and clean to avoid the toxic residue left mostly by the primer.