Reservoir or Wellspring?

I realize that lately I have been treating my creativity as if it is a reservoir from which I can only draw so much before it is used up. Maybe even that isn’t right–maybe I’m acting as if it is more like a canteen in the desert: when I’ve drunk all of my ideas, I will die of thirst, so I’d better drink sparingly.
So what is the truth of it? Will my ideas run out if I try to drink too often? Or will they only flow freely when I keep the well primed?