Every day I post a picture of Coop (on Instagram) in his carseat to help promote proper carseat safety! :) Always make sure the crotch buckle is aways secured right at the crotch. Never to low. Never on the belly. The chest clip needs to be right the top of the armpits. Make sure you cannot pinch any access strap and it is snuggly against baby. Rear face until *at least* 2 years old. height and weight have nothing to do with bone/muscle maturity. Never use products like strap cushions that were not made by the same car seat manufacturer for use with the same seat. Never wear a coat or jacket in the seat.