In our recent review of booster seats, we found a disconnect between the minimum weight limits allowed by manufacturers and what we would consider best practice for booster use. Of the 34 booster seat models in our tests, 28 state a minimum allowable weight of between 30 and 33 pounds. Current growth charts, however, show that the average 30-pound child is about two-and-a-half years old, far too young to move a child out of a seat with a harness, according to our safety experts.