Car accident; a year and a half later, a board fell at home and hit me in the head; another year and a half passed, and I exited via a too-short cellar door, which was about a year ago; and a couple months ago, fell asleep sitting on the edge of the bed talking to my wife and fell forward hitting the bookcase.

Need a helmet. And, actually, am wearing a ball cap -- it helps shade my eyes, as bright lights cause headaches. It also serves as a "sensor" of sorts; not quite as protective as a helmet, but it does protect somewhat.