I stumbled onto this youtube video from Southernprepper1 awhile back. Like all of his stuff it is well thought out and enjoyable.
My thoughts on ammo numbers where I am personally happy are already on the record. The question of pwhen to stop freaking out about a lack of ammo is an interesting one. My favorite part of the video is how Southernprepper 1 focuses on keeping things in proportion with each other. Having no food and a bunch of ammo isn't smart, neither is the opposite. Having a ton of ammo and no emergency fund isn't smart either. You must have balance. Get some food, buy some .223 ammo, get some batteries/ cans of fuel, buy some food, pick up a spam can of 9mm ammo, buy some silver, get some hygiene stuff then buckshot and an ammo can, pick up more food then repeat.
Also I appreciate that Southernprepper 1 recommends being realistic about what kind of weapons you can afford. I do believe in digging deep for important stuff but you do have to be honest with yourself about your situation. Scraping up enough money to get an AK or an AR and only having 2-3 magazines and a hundred rounds is not a good place to be. If you will have money to get more mags, ammo, etc over time then go with it but if things will be tight for a long time get a gun you can afford to outfit with ancillary stuff (mags, sling, etc) and a decent amount of ammo. Sort of like kids you shouldn't have them if you can't afford to feed them.
I do sort of have an issue with the recommendation to base ammo numbers on a given amount of reloads. I think this leaves folks using guns that carry fewer bullets short. For comparison a Glock 19 holds 15 rounds in the magazine so 15 reloads (the number given in the video IIRC) would be 225 bullets while a little snubby .38 would only need 75 bullets. For a rifle with a 30 round mag in comparison to a 5 shot lever or bolt gun the difference would be 6 to 1! A person might argue that folks using guns that hold more bullets are likely to use more in contact (I think fire discipline is a software issue vs the hardware of guns and their capacities) however they will probably not use more rounds hunting, confirming zero's, practicing or whatnot.
Anyway I enjoyed the video and like Southernprepper 1's channel a lot in general. You should check it out.