As ive said before, there is a proviso with low mileage cars.
If its been used every day of its life to do 2 miles each way to the shops for 10-15 years then its probably ready for the bin. Too many cold runs, condensation build up in the engine, rusted exhausts, just as worn an interior if the car had done 150K or whatever due to people constantly entering and exiting the car. Probably lacking a few oil changes and in desperate need of a cambelt and full service. No doubt a car which is driven in all weathers and then parked up in the garage and left to sweat while wearing most of the grit and salt under its arches from last years winter, just lovely!
I know a good few cars like that and would not want to buy any of them.
So use, as well as driving habits are crucial. Though without actually getting the owner to drive you about in the car before you buy it, your not going to know if they spin the clutch at 3000rpm at every junction or rev the car to rpm at every gearchange ...
We used to have a customer with a 2.1TD Xantia hatchback, ive never been in a car with anyone who changed down gears at such inappropriate times, with the revs flying round and into the limiter at times, very scary and unnerving. It was an extremely tidy and low mileage car though.
Find a car which has been cherished, garaged, cleaned and driven on a second or third car basis and your onto a winner, usually.
Your very right in that a lot of components are an age related item and will last 10K miles or 200K miles but are expired in years rather than miles. Strut tops seem to be a good example of this.
In reality you shouldnt be worried about an exhaust, thats not an expensive replacement and its expected. A clutch, well if you can feel the clutch is good on purchase then unless you give it grief by means of riding it or towing heavy loads then it should last a good while. I dont consider 80K to be the average clutch life at all, maybe if it has a DMF
Our van has 108K miles and has not even needed the clutch adjusting once in that time, it still bites well and in the right place, this is a vehicle which has almost always had a heavy load. Mind it is a basic XUD but its down to driving style. So you will quite easily find a car which has done 80K and has a worn clutch, then again if its owner has been that bit lighter it will get to 130-150 on the original and then slip, or if its treat with the upmost respect it will last longer.
As I say, its about condition and what you find on viewing and driving. Im sure most of us on here have traveled around the country looking at cars with the intention to buy, only to discover what was described as a good car to be a load of rubbish, no matter what the mileage or service history stamps are like. It just so happens that most of the cars I prefer have lower mileage, these dont always turn out to be good.
Indeed one XM I went to see had done 2 miles between MOTs, that wouldn't even of got it to the MOT station.... It was knackered and the 700 mile round trip was a total waste of time!
Buy on condition, thats the most important thing and what I stick to. The fact Ive had a few low milers is due to them ones being in good condition. The fact they are low mileage just makes them more desirable to me.