In my comments section, Lindsay asked me a question about cloth diapers. If all-in-ones are the most convenient, why not use just that type? Is the cost differential really that great?
There are a few reasons to get a variety of diapers.
1. What works for one baby, or at one age, may not work for another. Fitted diapers are generally better on newborns. Some diapers work better on babies with thinner or fatter thighs, or with a higher or lower waist. And all that may change as they get older.
2. Convenience isn't that big a difference (at least in my opinion) with prefolds vs AIOs. Though AIOs work more easily with squirmy babies ;)
3. And the cost differential, broken down below
So here's the cost breakdown, per abbyslane.com:
Thirsties (sized) all in one: $18
Blueberry one-sized all-in-one: $25
Thirsties Fab Fitted: $12-14
Covers: $11.50 (Thirsties), $15-25 (wool)
So those are some of the reasons for all the differences. There are some people who do nothing but prefolds and covers. I'm not one of them ;) I'm too addicted to the pretty patterns.