No need to ever take the mask off during live play IMHO (and seemingly most higher profile catching coaches these days). Advancements in design, practicing with it on and plenty of real world experience (often caught on video) that lends credence to the safety and effectiveness of leaving it on. Removing the lid when addressing the team pre-pitch to get their attention, be heard better and get the all important face time on video is important of course. ;-) I expect the usual suspects will take issue here, so bring it.