A shooting buddy of mine and I, stopped on the way home from a range at a bar, and over a few pints we got into a realistic conversation of just how much ammo is enough. I am talking about real numbers not just some off the cuff reply.
We wern't talking about some "survival" scenario, or war, or anything like that. We basically said, here is how much ammo we shoot now. It stands to reason that when we retire and have more time, we will probably shoot more. Then we discussed how much more ? Took those numbers and calculated what that comes out to per year. Then we guessed how old we might be where we would still be physically able to shoot like that.
For the two of us, who are both avid shooters, the numbers are staggering. For example, I shoot several hundred rounds a week. Just for the sake of discussion, let's be conservative and say it's 200 rounds a week (I shoot more than that, but for the sake of discussion). That is 10,400 rounds a year. I would say I could easily do that for another 20 years. Probably longer, but definitely 20 years (barring me getting killed 10 minutes from now or something). That is 208,000 rounds.
So, if I were unable to buy any more ammo, starting right now, I would need to have 208,000 rounds of ammo on hand to continue to enjoy shooting at that rate for the rest of the time I am physically able to shoot like I do now.
Obviously this is just an example. But the point is that instead of saying enough is never enough or some cute/clever/edgy reply, you could easily make a educated guess as to how much ammo is enough.
One thing I can tell you: when these various shortages of commercial ammo take place, I don't have any shortage of ammo. I go to the range and everybody has a great time discussing how much I shoot when there is an ammo shortage. They can't do that because they thought they were being big spenders buying only enough ammo for one shooting session and not planning for a rainy day (which seems to occur every few years lately).