I would say no less than 24 for a newborn to get through 2 days washing. I ended up with about 70 fitted/pocket/all in ones plus 3 dozen premium prefolds & 3 dozen infant prefolds. I am a huge fan of prefolds & covers for newborns & then moving up to the fitted/pocket/aio territory as they grow. What is your question on sizing? Some pockets come as one size that fit from about 10lbs to potty training others are sized like disposibles.