In the real world, every decent person should have a high-caliber rifle, a high-caliber pistol, a .22 rifle, a .22 pistol, and a shotgun at a minimum. In a family of four, that is 20 guns. If you may have others helping you in an emergency and cannot count on them bringing all the tools they may need, you should have a spare or two. If you may have different needs (ar-15 semi, bolt action, long range), you need more than the five basics I just mentioned.
And that’s just a start.
Since my personal SHTF, I've found that I lost the use 1/2 of my firearms because my arms became weak.
/johnny