I haven’t had a flat tire since last Spring but I got one on the Wednesday night GSTC ride. I’m comfortable changing tires, however, it’s not the fastest process in the world for me. The one I had last spring was a front tire flat and it was less than 5 minutes from flat to rolling out again (using CO2 cartridges). I don’t have much to compare that to but I thought was pretty good.
The flat on Wednesday night was on my rear wheel and I was on by older road bike. The rear wheel never seems to be as easy to remove as my tri-bike. My change time was closer to 20 minutes with tire irons that didn’t seem to want to get under the tire. After getting the tire back on the CO2 didn’t inflate the tire as much as I was comfortable with so I cut the ride short and it eneded up being a 40 minute ride instead of the planned 75 minutes.