Check The Glue in Your Patch Kits!
For those of you still running regular inner tubes. I had a flat 20 miles out, and one spare tube. When I saw that the glue in my PARK Patch Kit was completely dried out, I knew I had no choice but to turn around. Got at least two more flats on the way home, until my hand pump could no longer keep up with the leaks. Guess who had to walk about a mile in road shoes with SPD-SL plastic cleats?
Don't let this happen to you. Carry a sealed unopened tube of patch glue if at all possible, and check the tube often if you don't.