Did you know car seats have an expiration date? Car seats have a lifespan ranging anywhere from 4-12 years. The expiration date may be stamped in the plastic, on a sticker, or you may need to calculate the time based on the date of manufacture. Car seats are primarily made from plastic which can weaken over time – think of the lawn chair you left sitting outside in the summer sun and is now brittle and flimsy. Know exactly when it’s time to recycle that old seat!