How often should you check your rearview mirror while driving?

Checking your rearview mirror every 20 seconds is a recommended practice while driving for several reasons. This frequency allows you to maintain a good awareness of your surroundings, particularly the traffic behind you, which can help in making informed decisions when changing lanes, merging, or monitoring the behavior of surrounding vehicles. By regularly checking the rearview mirror, you can spot any quickly approaching vehicles, adjust your driving accordingly, and respond appropriately to potential hazards.

This interval is also practical, striking a balance between staying aware of what's behind you without becoming overly distracted. It is crucial to remain focused on the road ahead and your immediate environment while still keeping an eye on what is happening behind you, ensuring safe driving and proper defensive driving techniques.