How long will a booster last before my child outgrows it?

Most boosters top out around 100–110 lb and 57 inches, though the Britax Highpoint stretches to a 63-inch standing-height limit per the manufacturer specs surfaced by reviewers. Realistically, specialist communities note that fit-to-child (belt sitting flat on the shoulder and low on the hips) matters more than the printed maximums.