I have been cloth diapering my 15 month old baby since she was 3 months old, and after endless research these were the first diaper covers I bought. I bought size 1 with snaps and they were my favorite to use until she finally outgrew them around 9 months. We never leaked with breast-fed poop, and I don't remember it ever leaking urine either. I found the diapers to fit well at 3 months, and honestly, she could have fit in them before, had I been ready to try cloth-diapering. I did not buy the size 2s only because I had received other larger sized diaper covers as presents, but I might buy a few more of these for my next baby. If I were to have used size 2s, I would have stuck with the snaps because they can take off the velcro. When the baby is younger I strongly prefer the sized covers like this instead of all-in-one-sizes. Ease of Use There is definitely an adjustment for any parent new to cloth-diapering, but these were pretty easy to get used to. I often used with a prefold in jelly roll fold. Leak Prevention I don't remember a single leak. We always used these covers when going into the car, because that is prime location for blow-outs, and these are tight with the double leg gussets! Absorbency Honestly, the covers don't have much to do with the absorbency...so I gave it a 10 for keeping it from leaking so that the prefold could absorb and do its job.