First part, I like knowing how much ammo I have and of which caliber. As of today, 13,470 rounds spread across 18 calibers. Let's say I decide to drive out to Cabelas, and they have a sale on .44 Magnum. I look in AmmoBase and see I only have 40 rounds of .44 Magnum left. I can also tell that the ammo (Hornady LeverEvolution) was purchased at $1.05 per round. And if I really look, I can see pricing and where I got it from. Better way to make a decision on whether or not I want to buy.
Let's also say that Cabelas has American Eagle XM193 on sale. Say that 100 round boxes are $99... which is not realistic, but making up an example. I look in the app and see I have 1,100 rounds of that, and another 60 rounds of Federal XM193. The American Eagle was picked up at Cabelas for $42.99 a box ($0.43 per round). The Federal was $10.99 per box of 20 at MidwayUSA ($0.55 per round). Don't need it, nor should I be hosed with that pricing.
Having that info really makes better purchasing decisions in regards to ammo.
Second part, I store some ammo in my safe. It is pretty much spam cans, as I want weight in my safe to make it harder to flip (I have it bolted down, so it is just extra benefit) and protect easily removed ammo cans that hold a crap load of ammo. They also bump up shorter guns so it is a little added benefit with that.
I store the rest of my ammo in plastic ammo boxes that I've got from Cabelas over the years. Numbered so that I link ammo in AmmoBase to one of the boxes, so I can quickly grab what I need.