This is very difficult but since one is a mechanic and the other, a computer scientist, let me intervene and suggest the Turing theorem involving when a computer halts. A. Turing proved, in a remarkable but tricky manner, that it is utterly impossible to write an algorithm, which a decade later became a computer program which will predict when a computer halts or stops.
Am I right or even close?
Okay, it's kind of like MTBF, Mean Time Between Failures. No one knows exactly when a part is going to fail. But if a ball joint fails at 100,000 miles, and the other one at 150,000 miles, it appears that they both failed at the "same time," that is, in the same lifetime. So if you are going to get out the grease and jacks, might as well do both of them. Now a professional mechanic, OTOH, who has his tools handy all the time might not want to waste 15 minutes if it's going to take another 50,000 miles for the second bearing to fail. Also, ethically, it's a little safer to take that route for the mechanic.
Did I make it better or worse?