DD 1 who is almost 5 currently has a Britax Pinnacle 90 click tight car seat
DD 2, who is turning 3 in a few weeks , is in a britax advocate
however I am looking to upgrade DD 2's car seat
so ....
do I buy DD 2 another britax pinnacle click tight seat or do I give her the old britax pinnacle 90 click tight seat and get DD1 (who is almost 5) a new car seat?

If yes for a new car seat for my older daughter , which one???