Not everyone has the good judgment to know when it's time to go. Nothing is sadder, for instance, than watching an athlete past his prime continue to struggle to recapture the glory years.
But Frank Lautenberg demonstrated that good judgment when he announced recently that he would not seek re-election next year to the U.S. Senate. The New Jersey Democrat was first elected in 1982, retired in 2000, and came back to the Senate two years later, when Sen. Robert Torricelli, D-N.J., dropped his re-election bid amid ethics charges.
Lautenberg is 89 and has recently had bouts of bad health. It would be disingenuous of the senator, who accused his 1982 opponent, Millicent Fenwick, then 72, of being too old for the office, not to admit that age affects the ability to serve.
He was also facing a strong primary challenger in Newark Mayor Cory Booker, who announced his interest in the Senate seat in December. While Lautenberg at first showed his characteristic campaign style by taking a few jabs at what he saw as Booker's disrespectful jumping of the gun, he apparently later realized it was time for a graceful exit.
Lautenberg was a self-made millionaire before going to the Senate. In five terms in that body, he has been a staunch defender of liberal values. He has taken on big issues and big adversaries, on the national stage and in New Jersey.
He and Gov. Chris Christie have sparred over various issues, most notably when Christie pulled out of a rail-tunnel deal with New York and when the governor announced plans to merge Rutgers-Camden with Rowan University.
Lautenberg's decision to retire may have been influenced by a recent poll that showed Democratic voters favoring Booker in a hypothetical primary battle. He also knows that if he were unable to complete another term - he would be 96 in 2020 - Christie (or a future governor) would be able to appoint a Republican to serve as interim senator.
Lautenberg will be remembered for fighting for a ban on ocean dumping, which has improved the quality of life at the New Jersey shore. He pushed to prohibit smoking in federal buildings and on planes. Those laws led the movement for smoke-free restaurants, bars and workplaces. He worked to strengthen drunken-driving laws and raise the drinking age to 21.
And he's not done yet. Lautenberg has been a consistent opponent of the powerful gun lobby and is expected to be in the thick of the battle over reforms to the nation's gun laws this year.
When he retires next year, he'll also be remembered for knowing when to pass the baton onto the next generation of political leaders, for knowing when to say goodbye.