Ds was 7lbs 10 oz and wore preemie prefolds for a couple of months, I think (didn't keep close track). He is almost nine months old now (probably 20lbs or so) and I'm still using infant cpfs for him. Snappis haven't worked for a long time, but trifolding is nice and easy. These days he wears an infant cpf with a preemie cpf as a doubler. It's about time to move up to premiums, but they just seem so huge to me! I'm not big on bulk.