The longer you keep a car, the more value you get from depreciation. My neighbour paid £22,000 for a VW Passat Estate (all bells and whistles) in 2007!
He has spent approximately £3000 on repairs (excluding servicing) A cost of approximately £1,500 a year.
If he had traded it in at 3 years (50% depreciation) The depreciation would be £3700. But do have in mind what £22,000 would be worth now?
Imagine buying a car for £3500 and keeping it for 5 years with no extra repair costs - possible with a Lexus!