Do I need to change all four tyres on my 4x4 at the same time?

is it really true that if you get a puncture on one tyre on a 4x4 you have to replace the other three tyres otherwise the 4x4 differential will be damaged due to the different tyre depths?

My new car came with worn tyres - what should I do?

I took delivery of a new Ford Focus Estate fitted with 17-inch Michelin Primacy 4 tyres. The car had 8 miles on the odometer upon delivery. However, when I got home the tyre tread looked unusually threadbare....