Directing is a young person's game. There are exceptions, of course. George Miller directed the recent "Mad Max" as he was turning 70. Ridley Scott helmed "The Martian" and "All the Money in the World" on his way to 80.
Sidney Lumet had them both beat.
Lumet, who is always listed as one of the best directors never to win a competitive Oscar, has been making movies since the 1950s. Among his long list of credits are "Twelve Angry Men", "Serpico", "Dog Day Afternoon", and "Network". In 2007, when he was 83, Lumet finished his career by directing the critically-acclaimed "Before the Devil Knows You're Dead".
Of course, as with any director, not all of the movies could be winners. One of Lumet's duds was Melanie Griffith-as-undercover-Hassid in "A Stranger Among Us". Not exactly the best way to explore your Jewish roots on the silver screen...
Perhaps he kept working into his 80s to make up for that misstep?