When typing, do you double space after a period?
Don’t do that!
The second space is not necessary, and the habit comes from the days of typewriters, when you needed that extra room to distinguish the start of a new sentence. Technology solved that problem long ago, so the extra space just makes your text look, well, overly spaced out. Writer and technology expert Farhad Manjoo, explains the whole typographical history that led to the space problem in this rant.