Venturing your work with deliberation sets forth the right mind to get it done productively. You can produce great things only through genuine deliberation.
Studying with the intent to learn is not the same as studying to pass an exam. The quality of a creative work completed just to fulfill a due date obligation will never equate to that done with deliberation.
With this, setting a deadline is irrelevant when you have an intrinsic purpose to complete the work. Often, placing this constraint is inimical to the result because of the increased propensity to limit the necessary options that shall be undertaken and resort to sub-par alternative just to speed up the work.
Accept sunk costs by scraping off deficient products to redo it better when you envision overall progress, not just to embellish your pro forma reports with on-time deliveries.