I full support PM but since most parts can have quite different lifecycles, I don't replace costly parts such as a water pump or alternator until there are symptoms of failure other than when I have to take parts like that off to fix something else. I used to do that many years ago and gave or sold the used parts, primarily to friends. Very often the part was still working fine after many more thousands of miles. There's obviously risk. AAA is my backup.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas