9 months. I waited as long as possible but he’s so long

My son is 6 months but he is very long we already got him a big boy car seat he got the “graco 4 ever” he loves it and fits so much better

We switched my son at 4 months

9m I switched him. He had the snugride 30, but once he hit 21lbs and 28in long he didn’t fit well at all

I switched my daughter at about 5 or 6 months.

I kept mine in an infant seat past the first year bc she was within limits. When you make the switch to a convertible car seat rearfacing, the angle isn’t as reclined as an infant carrier. That can pose a risk of asphyxiation so I would just make sure your baby has solid neck and head control.

Just read the manual of the car seat for when you need to change them.

It took until almost a year before we changed their seats because they still fit in their infant seats.

If they still fit then there’s no need to change them yet. I waited till my son almost didn’t fit his and changed it.