Car seats are made of hard plastic, and like many things in our lives they can deteriorate over time. Unlike food and drinks, it isn’t against the law to continue using car seats that have passed their expiration dates (and there won’t be a warrant out for your arrest if you keep them past 10 years and 1 day after being manufactured), but there is a reason these Service Life guidelines exist: Car seat materials are designed to break down over time, making them less effective in a crash.
The longevity of a seat can also be affected by the conditions it is subjected to on a daily basis. From baking in the sun to banging against cup holders, the constant stress of everyday use can take a toll on the fabric and plastics, which can cause unseen cracks and weakening. The effects of extreme heat and cold can also make them brittle, which will decrease their ability to protect your child in the event of an accident.
Lastly, advances in technology occur at a fast pace and safety standards can change over the lifespan of a seat. If you are using a car seat that is past its manufacturer’s recommended expiration date, it may not meet the latest safety standards and could pose more of a risk in the event of a crash. Luckily, the majority of manufacturers have their service life dates listed right on the car seat’s label or included in the instructions manual.