Understanding the appropriate procedure and diagnosis codes for a particular study question is an important part of analyzing Medicare data. These codes are very specific and can change from year to year as new codes are added and others are discontinued.
There is no wear-out factor in the coil itself other than thermal cycling and the damage it may cause. Boots and wires do age, resulting in reduced insulation value over time. The key to correct ignition system diagnosis is to understand the details of how the system you are working on really functions. PAGE:
I also haven't heard of many ignition coil failures on this board. The coils internal resistance keeps increasing with use, if the metal inside has any flaws or imperfections it will ware faster and fail prematurely, thats why its often you have one coil go bad at 40-50K miles but the rest last to 120K.