Biking home from work today with a friend of mine, I got about 1/4 of the way home when my back tire lost pressure. I took it off and tried to find a hole, but it still held the pressure in. We started again and the rest of the pressure went out. He cut ahead of me with the intention of picking me up, but I beat him back. I ended up calling my wife to pick me up, somewhere near the halfway mark after trying to make a stop at Wheels Bike Shop. Closed, unfortunately, by a few minutes.
After getting home, I found the problem rather quickly: a small shard of glass had penetrated my tire and gashed the tube. If I had seen that on the road, I could have fixed it. However, I might have punctured a new tube in the process.
The plan is to get some thicker tubes - the thorn resistant tubes like the ones I put on my wife's bike. I previously blew out 2 of them running across rose bushes (don't ask) until I switched. No problems since. Maybe put some tire liners in as well.
The plan also included taking a spare tube - just in case.