I read an interesting article today that suggests that in some cases, it could take almost 30 years to recoup the cost of buying a diesel car through cheaper fuel costs. I am vaguely toying with the notion of buying a diesel for my next car, as I was under the impression that it would be cheaper, but this is making me rethink. I'm not planning on buying anything new for ages yet anyway but would be interested to hear people's views and experiences: which is more economic?