Never use more than one word space (space bar) after a word or period. This rule is without exception and agreed upon by all major style guides and typographers. Prefer I came. I saw. I conquered. to I came. I saw. I conquered. Double-spacing after a period comes from old typewriter habits and monospaced fonts, yet even published material from this era does not include a second space after periods. Extra spaces unbalance the text and draw unnecessary attention to their heavier emptiness. All writers, even ones not accustomed to adding two spaces, should run a word search on their completed manuscript to remove all double spaces. As with paragraphing, word spacing should remain consistent.