A gas mask is a real asset for any serious prepper. It’s an absolute must-have in case of a chemical or biological attack. Works just as well in a combat zone, as it’ll filter out heavy smoke and even dust clouds.
Martial arts can be more than learning combat moves for self defense: they’re great physical exercise, each form has its own philosophy behind it (which you can study along with the moves) and great fun. But for those of you who are planning on getting their money’s worth, you can ultimately become an expert in a certain fighting style.