It was funny for me, it was like a game of musical chairs. If you happened to be in a panel (the thing where they pick out the jurors) when the time ran out, you had to come back the next day. If you were still in the jury pool at the end of the day, though, you'd be dismissed. So you want to time your return to the jury pool just right. I luckily returned at 2:20 PM. One panel was called up at 2:45 PM and that was the last one called up all day (the day would end at 4:00 PM). But definitely a tense 75 minutes waiting to see if they'll call up another panel.