When should coolant be replaced?

I have a 2007 Jaguar XJ 3.0-litre V6 with 44,000 on the clock. Jaguar are saying that the engine coolant needs replacing at this service and are quoting over £100 to do it. When should the coolant be replaced...

Which luxury car is the wisest financial decision - Ferrari, Bentley or Aston Martin?

In early 2013, I bought a new BMW 640d M Sport Gran Coupe. I part exchanged it two years later for a new BMW M4. That cost me £32,000 in depreciation. I'm now thinking of selling my M4 at the three year...