I only have 4,000 miles on my new Triumph Thunderbird, and still had a fair amount of tread on the rear tire, but after picking up a large nail and being uncomfortable with using a plugged tire, I ended up replacing the tire this week. With labor the cost was $250, but I think I made the right decision. In the past I have found dealers are not willing to even consider repairing a punctured tire, I guess because of fears of liability, but my current dealer was willing to do it. The more I thought about the less I was confident of continuing to ride with the old tire with a plug in it, but maybe I was being too conservative. Anyone with experience or thoughts on the issue?