Hi, We have a MacPac Possum backpack that we've been using since DD was 6 months and they said we should be able to use it till she's about 4 yrs.

I must say that only when we tried on the different brands did we realise the difference between them. Some just suited our body shape (DH and I are both on the smaller side!) better than other brands. I would recommend trying some out in a shop before getting on eBay if you can.