Having had trouble with tire liners eroding the rear tube, I went with just a tube and a Kevlar belted Marathon tire. Somewhat to my surprise, that lasted for most of the riding season, but a recent trip had a protracted rest stop:
The puncture came from a knife-edged glass chip that avoided most of the Kevlar belt inside the tire:
I think even a tire liner wouldn’t help with this one.
Other than that, the tube was in fine shape, so I’ll probably patch it and toss it back in the bike pack. Tire liners prevent most flats from gashes along the midline of the tire, but …