[CSBM5]

It wouldn't be surprising that a large component of degradation is a combination of thermal cycles plus total hours of use -- both of those are likely much better indicators of life cycle than simply "mileage". If an N52 does 50,000 miles of city driving in a very cold climate versus a mild climate car that does 50,000 miles of steady state highway cruising, the results of pump life have the potential to be dramatically different.

The city driven car can potentially have many multiples of hours of operation, perhaps mostly short thermal cycle hours too, compared to the highway driven car.