Reading through this there seem to be a few tales of multiple punctures and concerns about having these. Does this really happen to folk?
If I get one a year I consider it a bad do. I once went seven years without a puncture. This year I've had four - a double puncture when I hit a very deep pothole at speed and two occasions when I hit glass which shredded the tyres. Highly unusual for me to suffer like this.
By multiple punctures I assume you mean on the one ride, or straight after fixing one.
Very rarely, as I check the tyre for debris carefully, so the two carried tubes are usually fine to do just do a swap.
I once had a hell of a lot of punctures on a ride Oxford to London with a pal so was reduced to doing multiple roadside repairs. He was very patient. That may have possibly been caused by a spoke/rim tape failure.
Very important when you get a puncture to check which side of the tube has punctured - rim or tyre side.
If I've ridden through anything dodgy looking I often stop to turn the bike over