My Brooks B-17 Champion has about 1,200 miles on it. My wife borrowed my bike to do a sprint triathlon (12 miles cycling). I forgot about her riding on the Brooks with a wet swimsuit. Afterward, I went to sit on it the Brooks sagged badly. I let it dry out for three days -- it stiffened up, but has much more of the "hammock" effect -- quite comfortable, although I'm going to lace up the flaps to get it a litte more taught.
Seems like riding on it with a wet swimsuit aged it five years