How do players know when/how to change lines in a hockey?

In higher levels of hockey, the lines are are typically set: Forward Line 1; Forward Line 2; Forward Line 3; Forward Line 4; Defense Pairing 1; Defense Pairing 2; Defense Pairing 3; Power Play 1; Power Play 2; Penalty Kill 1; Penalty Kill 2; At the higher levels the players know that each line designation is typically based on skill, so the coach sets them accordingly. read more

Players at the NHL level are smart enough to know their fatigue limits and when its strategically smart to get off the ice for a change. Shifts are 30-45 sec/ this is not by accident, this is just generally when fatigue sets in and its time to get fresh legs out. read more

Each team/line will have a signal from one of the coaches which will trigger the change. When the player closest to the bench hears the signal he will change his replcement will move to the play and signal the other linemates to do the same. read more