Always find new areas in your work to create contrast. Contrast will aid in providing a more richer reading experience of the audience, delaying the message or motive within the frame. For example in animation we use phrasing to develop a change of pace with a shot so that contrast is provided at a detailed level.
Your final work will work without a consideration of contrast, but may not be remembered.
Image above: Adolph Gottlieb, Blast, I, 1957, oil on canvas, 7’ 6 x 45 1/8 inches