The most common reason for a new seat is simply that your child has outgrown their current one.
5 Signs It’s Time to Switch to a Convertible Car Seat - Chicco when to buy a new car seat
Knowing when to buy a new car seat is critical because safety standards, child growth, and the structural integrity of the seat change over time. Beyond the obvious "major accident," there are several specific features and indicators that signal it is time for an upgrade. 1. Height and Weight "Limit Buffer" The most common reason for a new seat
: For rear-facing infant seats, a useful "feature" to check is the space above the head. You should buy a new seat when there is less than one inch (about two finger-widths) between the top of the child’s head and the top of the seat shell. : If the shoulder straps sit more than 2 cm (approx
: If the shoulder straps sit more than 2 cm (approx. 0.8 inches) below the child's shoulders when the headrest is at its highest position, it is time to transition to a larger toddler seat. 2. The Expiration Date Label Every car seat has a literal "best before" date.