As to how many are enough, it depends. For me, in a theoretical SHTF scenario for instance, I could happily make do with my Super Tinker, Charge TTi, ZT550, S5LE and a 911.

If I was going bush with the family, then I'm going to want to double up on some of those categories for my wife and kids. For instance, my ten year old son recently started coming along on hunting trips. He carries a Fallkniven F1 for now but will grow into some of the others I have as time goes on.