At 3:44 on an August morning in 2007, former NASCAR champion Dale Jarrett suddenly woke from a sound sleep.
"It hit me then," he recalled. "It's time to retire."
Jarrett was 50 at the time. He was struggling to recapture his past glory at the track and had overtures to be a NASCAR television analyst. So thoughts of leaving the race car had been building before he bolted awake.
Every driver has his own reasons for deciding when it's time to retire, of course. But Jarrett said he does not expect Jimmie Johnson, Dale Earnhardt Jr. and the other top veteran drivers now competing in NASCAR's Sprint Cup Series to collectively keep racing to age 50 and...