Some months back I moved into a new town. It's closer to work by about half, but I have managed to get twice as many flats between my S.O. and I than before. This is because of all the broken glass on the roads and sidewalks.
Subsequently I have gone to using both Schwinn brand self-sealing tubes and Sunlite brand "Thorn resistant" tubes. Both seem to have survived, though for whatever reason Sunlite has shorter valve stems, which makes it impossible to use my floor pump with my "aero" style rims. Hm.
Anyways, I'm looking into kevlar tyres and belts to supplement the thick tubes / self sealing tubes (might spray some self sealing stuff inside the thick tube - double protection, right?). I've read kevlar tyres have a higher rolling resistance and poor "performance" (though nobody who's said that has qualified "poor performance"). I haven't any data on the kevlar belts though.
Between belts and tyres, which works better? Can you double up?
Also, what about metal tire inserts? Basically a band of flexible steel, not unlike cable bands.