A lot of it also depends on how well u treat the engine. If u run it too hot quite frequently, then obviously its gonna drastically shorten the lifespan of the nitro engine, but if u run it cooler, and run it a bit on the richer side, then u will get a bit longer lifespan. It also is dependent on what kinda quality control is used to inspect these engines because as we all know, not all of the nitro engines that come off the assembly line in the factory are gonna be a good one. There are those that unfortunately do slip by quality control and end up in the consumer's hands anyway and unfortunately thats where we end up having to deal with that misfortune.....