I've only worn out one saddle, and I bought it used, a Shimano PRO Turnix AF. It was fantastic for it's whole life, then one day it developed play in the sockets where the rails meet the saddle, which allowed it to rock side-to-side as I pedaled. I'd never gotten a saddle sore, and got more than one in just one day. I had that one about 6,000 miles, but no idea of it's life before I got it.

I've also broken a Serfas Ghost, which was a fantastically comfortable, but very, very light saddle, and it snapped on the left-hand side, right along the overly large cutout.

I'm currently on a Selle Titanico X, at about 2,500 miles, and I've only put one full turn on the tension bolt. So I'm cautiously optimistic.