The decision can be dependant on the drying environment. If your environment is to dry you might want to keep the leaves on to hold in some moisture to ensure they buds don't dry too fast.
I've found when I've got my environment correct that I get my best results by removing all the leaves without atleast 50% trichome coverage. So all the fan leaves, and any smaller leaves that don't really have many trichs on them. That all goes into the compost, or it can be juiced if the leaves are healthy.
Then the whole plant or branch sections depending on how I"m cutting it get hung to dry for usually about 7-10 days. When the outside is just slightly crispy but the center is still soft I break them off the stems and put them in a paper bag to equalize the moisture. I'll give them a stir every day and leave them in the bag until they are perfect to smoke(usually 3-5 days). Once they are perfect to smoke, they also smell and taste outstanding, and it goes in jars to preserve that!