A simple thing to do to help prolong the longevity of your spark plug threads is to use a little Anti-Seize . I used it for years on all my dirtbikes so I figure why stop there . I have never striped a thread in that area . Note: I'm knocking on wood right now .

One trick is never use anything but fingers to get plug snug , then use a wrench . Another cool trick is to get some very flexible thin tubing to go over the ceramic portion of the plug if an extension is needed .This will allow the feel as if your fingers were on it . Fuel line works good on glow plugs for an extension too , especialy on saitos .