Hey mamas, I'm a car seat tech, so please know this is from a real source. Unless otherwise stated on the seat, they expire after 6 years. It's not against the law, but it's very much not recommended to use an expired seat. I wouldn't tell any parent to do something that I don't do personally--I would not use an expired seat. Even if the seat looks fine and has been well cared for, plastic and styrafoam degrade. It's not the harness we're worried about (although after 6 years I've yet to see a harness that doesn't have horribly twisted, crusty straps), but the shell of the seat and the foam that provides impact protection. Same goes for bike helmets. I promise you that I really don't believe this is a scam by the manufacturers. Here's a little tip I give families to save money: buy a convertible seat. They are safe for newborns (most are 5 lbs minimum weight) and your baby won't outgrow it until they are 3 or 4 yrs old, depending on how big your baby is, how quickly they grow, and what the weight and height limits are on the seat. This also allows you to keep your baby rear-facing until at least 2 years old. If you want the convenience of an infant carrier, bring the expired seat with you (in the trunk so it doesn't become a projectile in a crash). You can use an expired seat for a carrier if there's nothing wrong with it, just don't use it as a car seat. I work at Children's Memorial Hospital and am the coordinator for Safe Kids Chicago. We provide free car seat inspections and we also have reduced cost seats available for families in need. They are $25 and we have all sizes to fit all kids--convertibles (rear facing then forward facing later), combinations (forward facing with a harness, changes to booster later), and boosters. Please call and leave a message at ###-###-#### and I will personally call you back to schedule an appt.
Hope that helps, I know seats are costly, but I wouldn't compromise on this for my kids.
J.