Here in the southwest thorn-resistent tubes and/or slime or airloc are pretty much required if you're gonna ride a bike. 1 of my road bikes has Kevlar tires, regular tubes and Air-Loc in them, my other road bike has regular tires, TR tubes and Slime. I would rather have the slight weight added to my tires and not have flats than spend time on the side of the road! Air-Loc is the "new" slime and is lighter in weight and doesn't congeal like Slime has a tendancy to do. Oh..and I have Air-Loc And TR tubes on my mountain bike. (we have these Reaaaalllllyyy nasty thorns out here called goats head {picture a real goats head....you got it} that will take out Anything it touches!)

One suggestion would be next time you change a tube - run your tire lever around the inside of your tire and make sure you don't have something sticking through that could potentially flatten the new tube. That might help.