For years I've carried around a standard tire plug kit with its gooey "worms", reamer tool, etc. without ever having the need to use it. I thought I would tempt fate and stop carrying it around with me.
I didn't get a flat on the bike, but I DID get a chance to test it out on my car's tire, which got a screw in it. I seem to get those at least every 18 months now that I'm a town-dweller.
The good news is that the plug worked fine and was easy to install. I did it in my garage, otherwise I wouldn't have had a source of air to reinflate the tire on the side of the road. However, I found that the unopened little tube of rubber cement was practically empty and had just a few drops worth in it, barely enough to apply. Getting another patch kit would be in order before heading out on a motorcycle road trip. Also, on the bike I now carry a small 12V air pump in place of the old CO2 cartridges. Much more practical. Of course, last road trip I took I suffered a dead battery...