I agree with this; no matter how well prepared you are once some of the less fortunates figure out that you have supplies, they and more of their ilk will come. And even if you have plenty of ammo, you have to sleep sometime. As we proved with the Sherman tank in WWII, quantity has a quality all its own. If enough unfortunates are trying for you, eventually they'll get you.
Same as what I said above. If you shoot anyone that comes within 500 yards, you're advertising that you have something worth protecting and they'll come. And you have to sleep sometime. I'd rather use distance and stealth than trying to whack every nutjob that came trying for me.