I always believed that at around 9 months babies moved from an infant car seat to the next stage up. My lo is just 9 months so today I checked the maximum weight on the car seat. My lo is not big but I thought she'd needed to move up soon so I'd find out when and start researching the next stage. But it says the max weight is 13kg. My lo is no where near that. I've looked the seat up on line and it's advertised for use until roughly 15 months. Does this seem right? I really expected to have to move her up to the next stage soon. I know that where her head is also effects when to change seats but she's not near the top yet. It's great if I don't need to change seats yet because I really want to save for an erf one but I don't want to have some how read the information wrong.