I have some really slick Vredestein tires (meant for racing and not durability) and I've put about 500 miles on them so far, without a flat (knock on wood). This despite loose gravel roads, tons of glass, tumbleweed thorns and god knows what else I crunch over all the time. However, I put tire liners in my tires. Makes getting the tire mounted on the rim and changing tubes a little more annoying, but I have only had one flat ever with them in. Before I got these tires I had some Specialized stock tires - my front wheel had the tire liner insert and the rear did not - my rear tire had about 8 flats. I put the tire liner back in and.... no more flats.

I am a definite subscriber to the Church of Tire Liners!