The number of times per second a headset display updates, measured in Hertz (Hz). In VR, higher refresh rates (90Hz, 120Hz, or more) reduce motion sickness and create smoother visuals, which is critical for immersive play and comfort during long sessions. Lower refresh rates can cause judder and discomfort, especially in free-roam or highly dynamic content. In AR, refresh rate influences how stable and natural digital overlays appear when anchored to the real world. Because AR must stay aligned with physical objects, consistent refresh is as important as speed. Operators should look for at least 90Hz in VR headsets for comfort and ideally 60Hz or above in AR devices for smooth overlays.