plants will probably do what the "think" (through natural selection, the ones that do this will go on to reproduce, like a snake shedding it's skin) is best for their survival and ability to reproduce. Although you might want to trim some fan leaves to give light to the bud depending on your strain. I personaly leave all my leaves on because when they turn yellow that is the plant taking the nutrients, as a lot or you have already said, form that leaf for another part of the plant, ever notice that that leaves yellow form the bottom up?