I got over 6000 flat free miles from a set of Schwalbe Marathon (a bit heavy) and am currently at almost 2800 flat free miles with a set of Schwalbe Marathon Supreme. The Supreme model cost 2x as much but is about half the weight and give a more spirited ride. The plain Marathons still had life left in them, but I was ready to try a lighter tire.
Both tires crossed more than their share of glass strewn roads and bumpy trails.