why do carseats expire, but seatbelts don't?

I know that most carseats expire around 6 years. But what about regular seatbelts installed in the cars? What about airbags? Or other safety features? Do they expire?

good question!

my *guess* is that the car mfrs design their safety equipment to last a typical life-span of a new car-- somewhere in the range of 10-12 years? with car seats, the mfrs may take into account that they will not be used for more than a few years-- kids grow, and graduate to different seats; therefore to save costs (and pass those savings on to the consumer) the mfrs can use materials that may not hold up over time as well as the car's own materials. it's also a way of encouraging parents keep current with their child's seating needs.

Harness and seatbelt webbing do not break down at a very fast rate. Same with the bolts that hold a seatbelt to the car. There are cars out there with very old seatbelts that will still do their job.

The plastic in a car seat does break down over time. Somewhere between 6-10 years, the plastic will degrade enough that it will no longer be able to hold the harness and will rip right through the plastic. There is a crash test video of this somewhere, but since I do not bookmark them, I am no help. Someone here will surely show it, I am sure.

There are also changes in safety practices, making older seats obsolete. Stickers can fall off. Seatbelts have not changed dramatically over time, other than going from lap to lap/shoulder. The webbing and dynamics have not changed too much. There are no stickers to fall off.

I have seen it recommended here to have your belts replaced if you own an older vehicle. Or at least have them checked by a dealership/ body shop that has experience with belts. Always have a frayed belt replaced. Always replace a seatbelt that was in use in an accident. Some belts have a tag on them telling you to replace the belt. It can only be seen if some stitching comes out or something of that sort. If you see the tag, replace your belt.

Read your manual for information on your airbag. Some say to have the airbays inspected at a certain age. Others say to replace, others say nothing.

I was wondering the same thing today about car restraint parts expiring...because my SK Radian 65 manufactured on August 26, 2006 has harness straps that were manufactured in November 2005. So there is 9 months difference. It will be interesting to see what DOM will be on my new Radian and all of it's components, that is replacing my new Radian (I'm one of the 25-50 people who ended up with a seat that has straps 7" shorter than they should be).

Jacqui