FAQ: How often should I calibrate?

[Sam]

You should calibrate your participant before you start recording and only recalibrate if you need to. Drift-checks can be used between trials / blocks of trials to check whether the current calibration model is still accurate. If there is an offset between the gaze cursor and the drift check target (which is not corrected by asking the participant to look at the target) then the ESC key can be pressed and a new calibration performed. After the calibration, pressing O will resume the task from the point at which you left off to recalibrate.

Recalibrating in the absence of any indication that the current calibration model is inaccurate risks replacing a good calibration model with a less good model, so you should only ever recalibrate if you need to.