I'm sure you have had people tell you to keep talking the whole flight. That's not really true. My examiner told me before my flight that it's ok to have some silence to allow the "student" to think about things and concentrate. My examiner told me after the flight that many students make the mistake of talking about nonsense just to fill the silence on the checkride and it is not necessary. If your talking, make sure it's relevant to what is going on.