OP, you asked how much brass do we need and how to organize/store.
The first answer is how much do YOU need? Keep in mind that brass is the single most expensive component in reloading.
For some of us -- that is an awfully large number -- to the tune of whatever we can get a hold of and keep somewhere. Space constraints are probably one answer to that. I am by nature a brass whore/hoarder. I actually do believe that in some calibers I probably have more brass than I'll ever shoot. In some, the cushion is not as thick.
At this point, I am only picking up range pistol brass occasionally instead of on every outing. Now, rifle gets picked up every time and whatever else is around that is fair play.
Question 2 -- how to organize -- what makes sense to you?
You mention not drinking the regular coffee swill, but do others around you do so? Work, neighbor, friends? If so, then they can be the source of free storage containers. At my office, the ladies know that I am keeping the big coffee "cans" and the empties keep appearing at my desk for me to take home.
As you read above, many use some type of scheme that makes sense - keep like calibers in containers, zip lock bags, akro bins, etc. I also use a method as the one described earlier to mark what process that batch is on. There were some sample labels that were posted here some time ago. I modified mine to fit my needs and I print them out on plain paper in MS Word. Cut to size and then tape on the container. My markings use checkboxes and are mostly:
Caliber
Clean
Lube
Size/Deprimed
Belled
Primed
there are also some for rifle that have a mark for pockets swaged (military crimped brass)
My process is bring home a bunch of brass, if mostly pistol - toss into the sorter bins from Midway, toss into cans/bins by caliber, then clean in caliber batches. Once clean AL pistol brass goes into appropriate containers (do check/sort 45 ACP for primer size). 38 spcl gets sorted by headstamp, as does rifle. For rifle I use zip lock bags for each headstamp and then stuff those either in a big coffee can or ammo can.
Hope this helps...
EM