Maybe it's not a big deal in the 208, but in bigger turbines it's a big deal. Usually fuel flow readings come directly from a pickup on a impeller, it works or it doesn't. the other indications for the engine, ether TIT, or EGT use thermocouples, after years of use they wear out and can indicate your engine is running cooler when it's really not. Thermocouples also wear out when they are exposed to high temps and sand contamination as well.