It is my opinion and practice to remove spark plugs, inspect them, clean and re-gap once a year regardless of what MB says. You can be certain they will not "freeze" in place that way. I cannot imagine leaving them in place for ten years. Asking for trouble, I think.

Against some advice, I also clean the threads and give them a spot of anti-sieze when reinstalling. Has served me well for many years of automotive and motorcycle maintenance.