Rear facing in the vehicle starts when a child is born and goes up typically until they have outgrown their convertible child restraint in the rear-facing mode. The recommendation from the American Academy of Pediatrics is that children should ride rear facing until 2 years old due to the safety benefits of facing the rear of the vehicle. When a child is rear facing, their head, neck, and spine are protected by the shell of the seat during frontal and side impact collisions. It is a serious safety advantage for younger children to face the rear. Many convertible car seats will be able to rear face a child until they are around 3 years old, and we definitely support keeping your child rear facing until then (if and when possible). Sometimes, however, it just doesn't work for your given situation and we totally understand that. Maybe you have to make 3 across work with the addition of a new child. Maybe your kiddo gets road sickness every time they ride in their seat and facing forward is proving helpful. Or maybe your convertible seat has been outgrown rear facing prematurely and you aren't able to go buy one that will last longer. If you have made it until 2, we think you have done well!