I try to limit my caliber list for simplicity/minimalism, fewer different "mouths" to "feed" means I can keep more of each type per gun....
.22 is shared between my 4 rimfire firearms (2 handguns-a revolver and a semi, 2 rifles-a boltgun and a semi), and I generally try to keep more than 5K rounds onhand, more is always better, I shoot .22 the most out of all my firearms
12-gauge I keep a mix of buckshot, slugs, and birdshot on hand, the birdshot is mainly used for trap and is what sees the most use
.45ACP is shared between my 1911 and my Ruger Blackhawk revolver, and since I reload .45ACP, it's my second most used caliber
.45LC, right now I have no LC ammo, but that will change soon, I intend to use it in my BH, and potentially get a rifle chambered in it for ammo commonality, i figure a nice lever-action .45LC could pull double duty as both a hunting rifle *and* defensive rifle, keeping ammo stocks simple
I currently have no long-range rifle, up here in Maine, the longest shot I personally would take is 150-200 yards, 50-75 yards would be more average, at that range, the 12-gauge would do fine for my purposes, I did have a .30-06 for a while, but was never happy with it, it was traded off to get the Blackhawk Convertible .45, at some point, I'll add a long range rifle back to the collection, maybe a nicer Savage 100 series with accutrigger and wood furniture, I wasn't happy with the poly stocked, non-accutrigger 111 I had
So, I keep on hand;
.22 (recreational/small game hunting)
.45ACP (recreational/defense)
12-gauge(recreational/defense)
I plan to add;
.45LC(recreational/medium game hunting/defensive rifle)
.30-30(medium game hunting)
and maybe .308/.30-06(big game hunting)
a total of 5 or 6 calibers should cover my wants and needs, if I had to drop any of my planned additions, it'd be the .30 calibers, .45LC should cover hunting/defense for anything short of Møøse* up here
* A Møøse once bit my sister, møøse bites kan be pretti nasti!