When performing CPR, it is recommended to switch positions and allow someone else to take over compressions and breaths about every 2 minutes, which usually corresponds to five cycles of 30 chest compressions and 2 rescue breaths. This switching helps prevent rescuer fatigue, maintains the quality of compressions, and maximizes the chances of patient survival. Additionally, rescuers should switch immediately if the person currently performing compressions shows signs of fatigue, such as heavy breathing, weakened compression depth or rate, or visible physical strain. The transition between rescuers should be as quick as possible, ideally taking less than 5 seconds, to minimize interruptions in chest compressions. Clear communication between rescuers is essential to coordinate the switch smoothly to maintain effective CPR throughout the process.