Not nearly as much as before SMPs. Schwalbe Marathon Plus. 3 sets. One set @ 700x28mm on my primary commuter. Over 7000 miles w/one flat. A 2" self-starting screw that nothing would've stopped. I ended up having to 'unscrew' it w/my phillips head attachment on my muti tool. That's how deep it was buried in the tire. I rode that tire for another year before developing a slow leak. So, I got a new SMP and have over 1000 commuter miles on IT w/no problems so far. Both issues were w/t rear tire. The 2 sets of 700x25mm have about 2000-2500 miles on them w/one slow leak Turned out to be a pinch-flat under the valve on the front wheel of my road bike. I think I took a corner too hard on a hot day. I over-inflate both sizes about 15-20 psi. That's what caused it, most likely.

So, in over 1.5 years w/about 10,000 miles I've had 3 flats. That's one every 6 months or 3,300+ miles. I'll take that average, anyday. Didn't realize things were going that well...knock on wood.

For the previous 2 years I rode on Nuteck airless where the only issues were broken spokes and greater rolling resistance. Would still be using them, but got tired of the grind. They're 1-3 mph slower depending on the psi rating and size. Still have one bike that's almost never ridden that still has them. I'm keeping it for after Armagedden. So, when I went back to pneumatics I lurked, asked questions and decided that the SMPs were the 'consensus' most flat resistant. One could argue cases for other brands, but I couldn't be happier w/t product performance. They're worth every dime.