On my training ride this afternoon I made an unscheduled stop to change a flat tire. I had been around 1800 miles this year without a flat. I inspected the outside of the tire. Seeing no signs of a puncture, and noting that the valve stem (Presta) had not been tightened, I add some air and rode a short distance before it when down again. When I removed the tube, I pumped in some air. Not finding the leak, I carefully ran my finger along the inside of the tire. The puncture was caused by a tiny thorn. Once located from the inside, I found the entry point on the tread. I was back on the road in about 15 minutes.
It was a very pleasant day other than the persistent 26mph crosswind with gusts that approached 40mph. I was on the Centennial Trail near Lemont. The trees near the river and the woods in other areas helped a lot. These tires are nearing the end of their life. Perhaps new tires will give me more flat free mile.