It just depends. I've gone many miles with no flats, and then I've had 3-4 flats on one ride. There are too many variables.

After going several years and many thousands of miles with only a couple flats, I've shredded two tires and had 6 flats in the last month. You just never know. Hopefully I'm done with that and can enjoy far fewer flats for a couple more years!

Az