I originally bought a cover and 3 pre-folds package as a cost-efficient option for my baby when she was 3 months old, and I did not like them very much. Although these are technically one-sized they looked quite bulky on a 3 month old, and the econobum prefolds were way bigger than the size 1 osocozy prefolds I had. I mostly used them as a back-up for when my other NOT one-sized diaper covers and prefolds were already used. However, when my baby became around 9 months these became my go-to! They started fitting better (and thus stopped leaking) and the covers dry out easily by an open window so that I can use the cover multiple times as long as there is no poop. I also think they are more comfortable for the baby because I don't see as many marks on her legs and bottom as my other one-size covers. I highly recommend for older babies because you can't get better affordability than this! Ease of Use The prefolds need to be used horizontally when the baby is younger and vertically when the baby is older. The vertical prefold is still long on my baby even at 15 month old and 90th percentile in height, so there needs to be a little folding and adjusting to fit, so it might be a little more cumbersome. Leak Prevention Great when the baby is older, but a little lacking when the baby is smaller and there are gaps around the legs.