Allen Repashy has mentioned he has some who were WC, guessed to be about 2 or 3 years old at the time. They were still breeding in their mid-teens. I have some F1 which I got in Jan '97 so they hatched in the fall of '96 and all of them are still breeding up a storm each year. The girls don't look worn out or 'old', they produce eggs without problems just like the younger ones. There's no sign of infertility in the males either.