Is it possible to predict how rapidly a car will depreciate? I have a 2014 Mercedes C-Class Estate, which I bought when it was a year old. It had already lost about £10,000 of its original value at that point. It has done 62,000 miles, has been completely reliable and runs as well as it's ever done. It's probably worth £8000-10,000. I see no reason to change it at the moment but would like to trade it in before it becomes worthless. I would imaging that there is an optimum point at which one should sell?