You know, I'll probably be chastized for saying this but I will anyway. I've never worried over the age of an airbag. The only concerns I've ever had with one is it's stability. You need to understand now, that I live in a wooded mountain area, and always have this vision of a deer running out in front of me (happened to my 80 240D) and setting off the airbag in one of my newer vehicles. Normally you hit a deer and though heavily unsettled you just come to a stop. I always pictured hitting a deer, a hefty enough impact at backroads speeds to easily set off an airbag, which blows your hands off the wheel at the same time it blinds and stuns you, which on windy mountain roads can easily send you kareeming off an embankment to a tree or dropoff.
I never cared much for them myself. Sound old fashioned? maybe....but that's my take on them, I'm sure there's others out there that have been saved by them who will swear on them, that's understandable too.
My wife got in a hurry and slid off the road, hit a boulder and went airborne into a tree @ 30 mph...her airbag never deployed....which was supposed to deploy at 25 or better mph. It was a cherry 96 Bronco. She was fine, very upset over losing her baby though. The first thing I did on the scene was to deactivate the airbag because I did not trust it, even moreso because who knows how compromised those sensors now were. The insurance appraiser was releived to see I did that, and mentioned a good friend of his had recently been killed while taking pictures inside a vehicle with an undeployed airbag that popped on a whim. I understand in certain scenarios they can help, but I think I prefer the sanctity of knowing I can maintain control of my vehicle and minimize damage and injury in an average collision.

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Chris
64 190D R.I.P.
80 240D W/617 engine -for sale
82 240D -for sale