When you are using a base of a hundred or more engines, each running for long periods of time, with an anticipated lifespan measured in the hundreds of hours, all with exactly the same gas/oil mix, you can see where a data base developed over a relative period of time could be useful to provide an indication of anticipated failure prior to an upcoming flight. That was about as much background as I'm both inclined and able to provide. Needless to say, this is not for "model" type engines but for those more "industrialized types. I'm still looking for the difference between the two, but I've been told that there is one