I've had my current road tires over a year and haven't had one flat (knock on wood). Cheap $20 Continental Ultra 700x23 and riding in an urban area. Riding those tires 2-3 days per week.for over a year. I keep them inflated to 120-130 psi all the time which helps prevent pinch flats and I guess I've been lucky. My fixed gear I have 700x28 thickslicks which are very puncture resistant. There are tires like Gatorskin that have great puncture resistance that come in 700x23/25 but usually if you go with a puncture resistant tire you are doubling your tire weight because it's got more rubber. I'm my road bike I just carry a spare tube and co2 and tire lever (don't forget that!)