I had not done crochet in over 20 years when I picked back up the hooks and got busy. Yarn can be spun fairly easily using a drop spindle and wool or angora hair if Wal-Mart ceased to exist. But for now I will buy it. Crochet or knitting are good skills to have. They can be useful in a survival situation if there is an extended grid down period. Yarn is something easily stocked up on in your preps when it goes on sale or from thrift shops. I have bought a lot of yarn at yard sales and such for just a few cents. It doesn't have an expiration date and can be kept in a plastic tote. As long as it is dry and rodent proof is all you need to store it.