As I age I notice more and more how much of touch typing involves my slowly failing left hand. For example, the left hand covers four more letters than the right, and the three most frequent letters (EAT) and seven of the top twelve (+RSDC) are on the left. As well, only one of the top seven (A) and five of the top thirteen (+SDHL) are on the central 'default' row, three of which (ASL) use the unathletic third or fourth fingers. None of the top eight letters and two of the least five (J and K) occupy the best position, the right-hand central row.