As good as it gets?
On that test, David Cameron flew home from Toronto last night feeling pretty satisfied.
The prime minister both impressed and slightly intimidated his fellow G8 leaders when it was revealed that he'd not just gone for a morning jog at their Canadian retreat but had then dived into the lake for a spontaneous swim.
On the summit family photocall, one leader after another can be seen asking him to point out where he'd taken the plunge. Clearly feeling his masculinity threatened, Silvio Berlusconi circulated a photo of himself posing in trunks - taken, it should be said, a few decades ago.
The image which gave the new boy the most satisfaction though was that of him aboard Marine One - President Obama's official helicopter - travelling from the G8 retreat to the G20 in downtown Toronto. While other leaders had to drive the over-140 miles, the prime minister's aides were boasting that the special relationship "had taken off again".
Back on the ground, the two men swapped beers - the outcome of a drawn bet about whose team would beat the other in the World Cup. They also swapped warm words about how David and Barack would work together.
And work together they must. Both men sense the mounting political pressure of the rapidly escalating death toll for their forces in Afghanistan and the steadily decreasing public support for their continued presence there.
On the economy there can be little doubt that the president felt more comfortable with David Cameron's predecessor than with him. If Gordon Brown had been at this G20 summit, he and Barack Obama would have stood together to warn of the risks of cutting support for the economy too fast.
As it is though, the president chose to help his new ally, praising him in front of other leaders for taking the "necessary courageous action" to tackle Britain's budget deficit.
The same officials who worked on Gordon Brown's summiteering now work with David Cameron. They've been struck by their new boss's cool, calm confidence on the world stage BUT they're quick to point out that he's benefited from the guilt felt at the White House about how they mishandled the first meeting between Brown and Obama.
What they've told the prime minister is that this may be as good as it gets.
The image of this summit that many will see at their breakfast tables this morning is of David Cameron with his head in his hands... when he watched England trounced 4 -1 alongside Germany's Angela Merkel.
If things do go wrong for him in Afghanistan or the economy, that image may well be used to sum up the fate of a hapless British leader on the world stage rather than to show the global new boy trying to enjoy the football at his first summit.