For scholars trying to be productive, one of the most important issues to attend to is the balance between generating the new, and completing the old. There is no magic formula regarding how much attention to pay to one or the other, yet some attention should be paid to both.
Those who start new things every day and pay no attention to finishing have lots of wonderful ideas but nothing to show for it. Those who pay no attention to new idea formulation tend to have large blocks of fallow time after an article is submitted. Both can be depressing.
My advice, assess your tendency and consciously work toward a balance between both tasks. Push yourself in the direction that runs counter to your tendency (if indeed, you find yourself not well balanced in this regard).