In tennis, a Change-Over is a 90-second break that happens after every odd-numbered game.
During this time, the players swap sides of the court. This makes the match fairer by letting each player deal with things like sun and wind.
Rafael Nadal is known for his detailed change-over routine of neatly arranging his water bottles and gear. Serena Williams once ordered an espresso during a change-over when she was feeling tired.
The change-over gives players a moment to rest, hydrate, and mentally reset between games.