Most child restraints (aka car seats) have an expiration date six years from the date of manufacture. Each seat comes with an instruction manual that you can refer to. Be sure to register each safety seat with the manufacturer.
A good rule of thumb is if you’ve had the carseat for five years, it’s time to begin looking for a new one. It’s also a good idea to double check relatives’ cars, grandparents’ and other family members’, especially if they’re using an older safety seat.
Why are there expiration dates? The components in the seats have potential to degrade over time. It’s also important to maintain current standards and technologies used.