I try to pick just enough to fill the dehydrator. This year I am taking the time to remove the sage leaf stems before drying. In the past, I would try to pick them out of the dried sage, but I always missed some, making them still usable but less desirable.
Removing sage stems
Spread leaves evenly on the trays in single layers as much as possible. Since the bottom tray gets the most heat and dries quickest, reorder the trays every few hours (sooner for thin leaves like parsley). The thicker leaves (comfrey and sage) require a longer drying time than the others. The ideal sequence (from top to bottom) for 5 trays is: 12345, 54321, 32154. Continue drying until the leaves crumble between your fingers. I dump them into a wide bowl, crush, put into snack bags, seal, date and label them (they will make good stocking stuffers in a few months).
For Italian parsley, I pick the entire stem (instead of individual leaves) and sit comfortably watching TV removing the leaves from the stems.
I have not undertaken drying fruits and vegetables yet, but for those who are interested in learning and want a good place to start, click here.