Tilda Swinton, 50, has been working steadily since her 20s, but her most mainstream roles in movies such as “Michael Clayton”and “The Chronicles of Narnia,” series came after she turned 40. “By 40, people know what you can do,” Swinton says. “And when you’ve been working for a fair amount of time, there’s a confidence in your own ability.” (Anne Cusack / Los Angeles Times)