“A lot parents try their best, and still can’t figure this out,” says Lorrie Walker, training manager and technical advisor for Safe Kids Worldwide. “Others may be thinking they can stretch an infant seat until they need a booster and save a little money.” But while there is no link between the cost of the car seat and its effectiveness, take the time you need to make sure you have the right seat for your child.

The fix:

1. Research seats to find one that fits your child’s age, weight, and height.

2. Check the manual and measure your child’s growth periodically so you know when it’s time to move on.

3. Follow the new American Academy of Pediatrics guidelines on how long to keep your child rear-facing.

4. Never buy a used seat. There’s no way to know for sure if it has been in an accident, and even seats that have been in the family may be missing parts, or expired. Car seats generally have expiration dates six years after manufacturing.