Quite often, I see mining spots with only one or two uses left on them. Half the time when I see other people mining, they leave as soon as the spot gets to a nub. My question is, why? I can think of a few possible explanations, some of which are clearly false, some of which I don't know.
(1) If you completely clear a spot, it won't grow back, a la wood trees. (false)
(2) If you leave a little left, when it comes back, it will come back bigger (???)
(3) There is a quest to finish off nubs, and this is done to make it easier for the people who need to do the quest (true, but pointless).
(4) The last few mines of a spot give less material/lower change of gems (???)
Are any of these the reason? Does it have something to do with how things were in the beta? Would I be doing a service by leaving nubs for people?