How many diapers is average in the first weeks/month?

With my son I changed him every time I fed him when he was a newborn and he ate every two hours so 12 diapers a day in a 24 hours is 84 diapers a week. I would buy 3 weeks worth of newborn diapers and then see where the baby is at then. I think my son was 6 weeks when I went to size 1-2.