OK, I am pitching this for opinions. There are at least two professionals on this forum with the right experience to let me know the answers - but I'm interested in opinions in any case.

So: I am running, and succesfully maintaining a 12-year old car that is still in excellent condition. I budget for repairs where possible, based on what I see in my service schedule. However: there are some items that are just not covered.

So, the question is: what is the serviceable lifetime of the following, and when should they be replaced? Bear in mind here that if I am going to replace these items, I have to do it now before the statutory EU service parts requirements for the car expires this year.

The items in question:

- the exhaust gas lambda sensor
- the exhaust catalyst
- the driver airbag
- the seatbelts and mechanisms
- the unipoint injector (petrol) in the in the injector body.

The car is 12 years old, and has covered 295,000+ km, and has been regularly serviced according to the service schedule. It shows the following symptoms:

- rich mixture on shutoff (injector? lambda?)
- slowly increasing fuel consumption along with a sooty exhaust (no oil burn, oil colour still good)
- slight dropoff in acceleration/overall performance.

I am aware that you could chalk up some of this to;

- worn rings (but this would go with increased oil consumption - currently zero)
- worn bores (ditto)
- incorrect valve clearances (about to be done - bucket and shim)

I'm interested in your opinions!