Danny White
Many people forget about White when they think about the Cowboys’ greatest-ever quarterbacks. The underrated star enjoyed a Super Bowl and also made the Pro Bowl during his career. Nonetheless, he arguably held on for too long before retiring (via Sportscasting).
In 1986, White began to deteriorate and struggled with injuries. Dallas returned him as their starter the following year but benched him because of his decline. He should have retired because the writing was on the wall yet he stuck around for another year and played.