My wife and I are expecting our first child, and therefore are expecting to purchase a car seats. My wife and I have discovered that car seats have "expiration dates": a car seat, no matter how lightly used, is deemed unsuitable for use after a particular date. We wonder why.
A car seat which has been in an accident could be compromised in ways that simple visual inspection could not confirm. I am not asking about these car seats. I am asking about the car seats which have experienced the repeated loading/unloading which comes from placing a small human child in and out of the seat and driving them about in a driving style that could only be described as "not aggressive."
Attempting to look up answers for this question have not yielded any satisfactory results! So I ask you, engineering stack exchange, why do infant and child car seats have expiration dates?
I have a few possibilities, but I have issues with all of them:
- The car seat is designed to withstand a number of cyclic loads, and critical car-seat parts have a fatigue life which the manufacturers base the expiration date on. This seems the most likely, but babies are really small and the materials are meant to protect them against high-speed crashes for the entire product life!
- The car-seat manufacturers are greedy, using social pressures and the label of "unsafe" to force parents (as a group) to buy car seats at regular intervals and deny the second-hand market any 'viable' material.
- Something in the car seats really does degrade with use, heat, or sunlight and therefore actually expires. (This seems unlikely, but terrifying!)
- Safety standards are expected to update after some amount of time. This particular explanation seems very odd to me: safety standards are set be governments and industry groups, and I doubt car-seat needs have evolved so much that a regular update every few years is entirely needed, or that those updated industry safety standards will always render old products unsafe.
Or maybe it's something else! Sources are welcome!