Cajun.... that is a pretty good way to sum it up.... it is the way that I, as an inspector for over 30 years now, have always accepted the rule regarding helmets as being....
The rule book also states this- "....Helmets shall be undamaged and in serviceable condition" This clause pretty much cover what you said about helmets that are heavily used.... The one thing that everyone needs to know and be reminded of too is that the materials from which helmets are made can and will "bio" and otherwise degrade.... sunlight, ozone, oils/fuels etc will all cause material degradation.... that is the reason for a minimum of annual inspection of helmets..... and even if a person is aldo a dry lakes competitor and has had his helmet inspected, I still like to quickly look at it- to see, if nothing else, that the inspection decal is still intact.
And.... some of us.... me included, may only make 4 to 7 runs in a year.... my helmet which is 10 years old and now retired (as well as the last one from the 90s) is(are) in near new condition... From the 70s, they are all lined up on a shelf in my downstairs "den"....
Have we all overwhelmed you yet?