Common sense dictates that one should have a tool in case it's needed, rather than wait til it's needed and then try go purchase the tool.
I don't NEED a hammer, I HAVE four of them. I don't use them everyday, but they are there in case I need one.
I don't NEED a chain saw, I rarely ever use it. But when I do NEED it, I can get it and put it to use in a moments notice.
I don't NEED a fire extinguisher, but I have one just in case.
I am safer WITH these weapons ( AR-15, 44mag, 380, 12ga) because if I need them, I have them. If I don't have them and I need them, Im screwed and so is my family.