The two covers I just purchased are my third and fourth wool covers because I loved the first two so much. I was really excited to find a natural, polyester-free option, and these work great! Since they take a while to dry after washing, I needed more than two to keep in rotation, and having four seems to be just right. I accidentally ordered the wrong size this time and had no issues exchanging them. I will definitely buy more of these when we need the next size up!