There's no such thing as a car you just put petrol in and drive it. Private transport is expensive - it's just a question of whether you want a fixed cost of a new car under warranty or take a chance on random costs (which are usually much less cumulatively) of an older car. Some folk like general newness, and I can see the attraction. Of course, some people prefer "new" to "actually nice" and wonder why the 61 plate registration alone fails to satisfy after 2 years when it's not new anymore and you bought a stupid generic car because it appeared to be a good deal. If that's less important, then running older cars is almost always better value for money.
Market value versus looming repair cost is a meaningless measurement because you can't just walk away without spending the same (and usually more) on a replacement car which invariably comes with it's own 'features' which will raise their head and demand cash. You're onto a loser when you start thinking like that, are are doomed to be permanently skint because you keep getting rid of a car just as you're getting it sorted in favour of the next bag of nails to pour money into.
Could not have said it better myself..