Nah, your actually pretty typical. The 7.3s seem to be able to get good life out of the glow plugs especially if they are Beru/Motorcraft. Wellman and Delphi do alright too, but Berus seem best. I finally ahd to replace one not to long ago, and the other 7 are still good. They have seen lots of starts as I drive this truck every day mostly in town, I converted to the 7.3 style system in 10/04, so that plug lasted better than 3 years and all the rest are still good as I say.