Because your new nation-state is going to need administrative forms and stationary of all kinds (including passport, copyright, and patent applications; including blank forms for proclamations, resolutions, and appointments) consider seceding on a Friday afternoon*. That way fleeing rebel bureaucrats have the weekend to pilfer enough office supplies from the old government to get your new government off the ground.
*The attack on Fort Sumter began on Friday April 12, 1861 and continued through the weekend.
(document from the Records of the Confederate States of America stored in the Manuscript Division of the Library of Congress)
