There have been times when the technicians at YES! Automotive in Houston have found spark plugs seized in the cylinder heads of some of our Houston area customers' vehicles with as little as 60,000 miles on them. The removal of these seized plugs can result in hours of labor by our technicians at YES! Automotive in Houston. There have been rare occasions when YES! Automotive in Houston has needed to remove cylinder heads just to get the spark plugs removed. YES! Automotive in Houston suggests that in order for our customers in the Houston are to maintain peak performance for their vehicles, that their spark plugs should not be run longer than 30,000 miles. YES! Automotive in Houston suggest that consumers should take those 100,000 mile spark plug marketing claims of manufacturers with a grain of salt.