In suburbia So Cal, there's glass from time to time. I've yet to get a flat, however, knock on wood! Not sure how much is luck, how much is being watchful and careful, and how much is not riding too far to the right where most of the debris (including glass) typically is.

Dh has warned me that some of the rocks that fall into the road in the hilly areas can be very bad for tires, these particular rocks more so than others, I guess ... so to be careful there. Shortly after he told me that, my friend got a flat and she thinks it was from hitting a rock.