Had chain/tensioner done a couple months back with my car only on 29k!
100% had the diesel sound when warm and it was cured by doing this work. So for me I guess it was bad luck or perhaps more a function of time (car is 10 years old now and I expect to change thigs due to thier age) rather than distance. For piece of mind though, and the fact it did actually make a difference, im glad I did it!
Engine is BWA.
As some other have said. If you havent got any of the symptoms,why bother? if it aint broke... (or rather; if it aint rattlin'...)