What i am curious aboot is why, if, due to the nature of your drive you need a car with decent ground clearance and 4wd, you have a Leon and are thinking about a used Leaf?. Neither of which have 4wd or higher ground clearance!. You either need this or you don't, and going by your own car, actually you don't.

Lets say you 'transfer' 15k miles off the Sorento onto something else. Fuel cost at 35 MPG and 1.30/l for diesel for these miles is £2530. If you buy something else that will do 50MPG say, then it's fuel costs will be £1770 - leaving only £760 / year to cover depreciation, tax, insurance, maintenance. Seems very unlikely that you can make that work as a saving, and even if it did it would be only a couple of hundred. Doesn't seem worth the effort to me!

You might also make the Sorento last 2 or 3 years longer before you feel you should sell it. I had a diesel CRV I sold basically because it had done 100,000 miles - had I transferred say 5,000 a year to an old banger then I could probably have got at least two more years out of it on that criterion. Changing that sort of car for new is an expensive exercise, you're usually writing a cheque for £15,000 or more.

That argument however does raise the question of whether there are better ways of saving money, if that is the objective. such as buying a Duster instead, or buying used.

Thank you all for your responses. The overwhelming advice is what I expected I guess...I'm engaging in man maths. I have no great lust for a third vehicle. I have to say though, there is an appeal in a "disposable" vehicle like SLO mentioned, especially the way the kids treat the car.

A smaller vehicle would tow the caravan (we started towing it with an Octavia Estate) but you get to appreciate that the heavier the tow car, vs the caravan, the more stable the unit.

So I don't think this works with an electric vehicle. It might work with an old Jap petrol hack, but I'm not so sure how keen my wife would be on driving that day to day. She'd probably take the Leon! I hadn't really thought about the savings in depreciation on the Sorento.

I don't think I'm brave enough for bangernomics. Which is a shame, as I'm also envious of those that do it! I helped my father in law puchase an 11 year old Touareg 2 years ago. He dismissed all my "sensible" suggestions to meet his criteria (CRV, etc.) and we were following a Touareg when he said "that's what I'd like, but I could never afford it". I made the mistake of saying, yes you could! His budget was 6k, I thought he was crazy spending 5k on an 11 year old 100k mile vehicle, admittedly with a good service history, but two years and 20k on, its running great and only burning a bit of oil! It also looks like a much more expensive car than it is, for what that's worth.

Unless you are a trader who can 'buy' trade-ins cheaply and re-sell later, you are better off keeping your cars as long as possible. Most money is lost when you sell a new or nearly new car only a few years after you bought it. As has been argued, a third car is more likely to cost than save money.

It sounds as though you do the lowest mileage, so it would make sense if your wife used the economical diesel for her long commute unless you have a lengthy business trip. In your situation, 'her car' and 'my car' might need to be re-thought. Horses for courses.