I have worked with infants and preschooler for years and these are the best of the best. These were the only shoes/booties on my baby registry when I got pregnant, and I couldn't be happier with them. I regularly get them for gifts. Baby socks and booties are always falling off, but these have a special adjustable ankle elastic and the way they are folded at the top makes them super secure. They are extremely well made, and the fur lining is high quality. I bought the 6-12 month size because I know the soft soles will help my daughter get her balance when she first starts standing and taking steps, but they are flexible and soft enough to be worn as booties and secure enough to stay on when she crawls. She is only 3 months old- her feet are on the longer side, but nowhere near big enough to fit it most 6-12 month size shoes, however these are secure and comfortable on her feet and the ankle elastic keeps them on. I fully expect to get 9 months of use out of them. Highly recommend. They are worth the price.