When somebody who has been there and done that, has the wisdom of age and the silver hair to prove it, tells you it's time to call it quits, you should probably listen.
Senator John McCain, the 2008 Republican presidential nominee who lost to Barack Obama, offered free advice to presidential hopeful Rick Santorum this week, saying it was time to make a graceful exit.
On Tuesday, Santorum lost the primaries in Wisconsin, Maryland and the District of Columbia to frontrunner Mitt Romney.
Since then, pressure has been mounting on Santorum to quit, to allow Romney to get ready to tackle Obama in time for the November general election. But Santorum won't go.
His home state, Pennsylvania, which he represented in the House of Representatives and the Senate for 16 years, holds its primary on April 24 - and polls show he has 37% support against Romney's 42%. Just four weeks ago, Santorum had 42% against Romney's 25%.
When even the people who kept voting you back into office for over a decade don't support you, it's probably time to say adieu.
But Santorum is still hoping to win his home state, thus increasing his chances of getting the Republican nomination in Tampa, Florida, at the Republican National Convention in August.
Actions speak louder than words, however. Santorum took a break from campaigning this weekend and didn't make any major advertising buys, which some analysts saw as a sign that he may back out of the race after all.
Losing the primary in Pennsylvania would be the a second blow for Santorum in that state.
Six years ago, he lost his re-election bid for a third term as a Senator to a Democrat, Bob Casey. Maybe Republicans in Pennsylvania fear that history would repeat itself if Santorum ran against Obama.
But Santorum says Republicans can only win back the White House if a true conservative runs against Obama. No prizes for guessing which true conservative he has in mind.
Pundits say a Santorum loss in the Pennsylvania primary on April 24 could even hurt his chances if he chose to run for president in 2016. A loss at home would be just too devastating.
Romney patrons are telling everyone that, come April 24, their candidate will be the last man standing. Romney's other challengers, Newt Gingrich and Ron Paul, hardly ever get a mention in the media these days, and their role will be even less significant in this race.
Gingrich still stubbornly asserts that he will only quit and endorse Romney when the frontrunner gains the 1144 delegates the winning candidate needs for the presidential nomination. That won't happen if Santorum stays in the race.
The primaries are getting boring anyway: everyone's looking forward to a Romney-Obama showdown, so Santorum really should just go home and start working towards 2016.