I believe that most manufacturers had 10 years as the lifespan for an airbag but most have extended that by another 10 years, presumably after seeing that they are servicable and nothing has degraded in that period.

I would second the suggestion of replacing the cat, especially if the vehicle is experiencing any overfuelling or performance issues. I suspect a main dealer would rob you blind for an OEM unit, so check with an exhaust shop to see how much a quality aftermarket unit will cost.

Gareth