wow 18 years no flats ...thats amazing ....i repair flats constantly .....i even have my own tire machine bcoz im always doing some kind of tire repair or change.
i have no idea where so much crap on the road comes from but i have pulled out everything from roofing nails to a sharp chunk of aluminum one time from flat tires ......
i am not talking about my car only i maintain all my family's cars so like 7 cars total and it seems there is some kind of tire work every couple weeks
i have become a tire connoisseur with all this work lol