On a recent day there were six times as many range bars in the half hour period from 9:30 to 10:00 eastern as in a half hour period later in the day. This also held true for tick bars. On a minute bar chart, the bars were much bigger during the opening half hour. The question I have is do most traders use the same strategies in the opening period as later in the day? Does it make sense to use larger range or tick charts for the opening period? Does it make sense to do nothing for the first hour or so? I would appreciate your comments.