Probably NOT a good idea, since you need to look straight at the camera with a neutral face for it to work, else things mess up. If you for example look to the left when the calibration is going, and you after the calibration look forward, your avatar will be looking to the right.

Periodic autocalibration is not an options since the user MUST assume a neutral facial expression and body positioning for the recalibration. If we were to NOT display the message for autocalibration, the user wouldn't know they need to assume this position and it would result in a bad calibration. If we did display the message, it would end up being spammy and overall unpleasant.

However, we will consider adding a hotkey for calibration.

I understand your explanation and agree, I had this idea based upon own experience when I mostly use FaceRig for gaming broadcast, that means I assume mostly the same facial expression, shifting only in specific situations thus fititng into possible time limit. This is, however, very narrow area of usage. Hotkey will be much suitable solution, thank you for that.