I know all babies are different, but we have been stocking up on a few bits and I have a few packs of 1, 2 and 3's in pampers and little Angels. My mum works in boots and they have 40% off all their own stuff in a few weeks to staff so thought I might get a few of boots ones while on offer. Anyway, approx what ages are the sizes for? They all say in pounds on the packs so size 2 say 6-13lb's, size 3 are 9-20lbs and size 4 are 15-40lbs! There seems to be quite an overlap in weight and I'm thinking perhaps size 3 I will use the most of? What sort of age is a baby usually 20lbs? I'm not going overboard and buying loads, we have 2-3 packs of each atm but in different brands as don't want to get all same ones incase one doesn't suit.