There is, in some ways, bit of an art to that. The players, Chara included, have to give everything they have in the moment, or there might be no more moments. They also have to make there is something, some energy, some extra motivation, in reserve.
Because one overtime could turn into two, could turn into three.
"You can't be really going on the ice thinking, 'Well, I'm going to save myself this shift,'" Chara said. "If there is a puck in your area or your corner, that's your job to win the battle and that's your job and you have to go full-out. If the puck is there for a full minute, you have to obviously be ready for that.
"But at the same time when the puck is going up the ice as a defenseman, you can see that if they have the numbers you're not going to be sprinting there. You're going to be closing the gap, but be smart about it. So at times you have to be smart, at times you see the chance and you've got to go."
That is why he trains the way he does, making sure that he is as fit as, or more fit than, just about anyone else on the Bruins, even as he has five or 10 or even 20 years on them, as he has on rookie defenseman Charlie McAvoy, who played the fourth-most minutes on the Bruins in Game 5, behind forward Brad Marchand (31:43), defenseman Kevan Miller (33:59) and Chara.
Those players are in their 20s, or in the case of McAvoy, 19.
Chara is 40. He played 36:46 on Friday. And after the game, his lip turning purplish, he was still standing and talking and, yes, smiling.
This is what he prepares for. This is what he loves.