A reader writes to ask:
I have always used two spaces after the end of each sentence and someone recently said they believed that was no longer the correct method to use. Can you tell me if I should leave one or two spaces between each sentence in a paragraph or is it one of those inconsequential issues?
I receive more email on this topic than any other. For such a simple question, it stirs up plenty of passion, controversy, and bile on forums where these sorts of things are discussed. I would like to advise you that it's an inconsequential issue, but clearly it is not for many writers and editors.
The roots of this debate go way back to the days of typesetting by hand, when two different styles of sentence spacing emerged. French spacing was the practice of setting a single space between sentences, while English spacing meant using two spaces. The two-space method carried over into the realm of the typewriter when that device was invented. If you learned typing on a typewriter, you were no doubt taught to put two spaces after every sentence, and two spaces after every colon, too.
In the mid-20th century, with type no longer being set by hand, most publishers reverted to single-spacing between sentences. That's still how your work will appear in print, regardless of whether you use one space or two in your manuscript. These days, since your work is likely to go directly to print from an electronic file, using one space between sentences in a manuscript is more common. This makes the process of converting your file to a format fit for publication just a little more smooth.
Still, for many of us who've had it drilled into our heads that we should hit that spacebar twice at the end of a sentence, switching over to one space can be hard. Personally, I don't think it's that important. Most typesetting programs that I'm aware of make it easy to convert two spaces to one in an electronic manuscript, so I don't feel much obligation to save the typesetter a few keystrokes. In nearly twenty years of selling fiction, I've never had an editor or agent tell me I need to stop using two spaces, and I have no plans at this point in my career to change the way I type.
That said, the two-space practice is on the way out and is going to die. But despite all the Sturm und Drang, the choice really is still up to you. The rule of thumb I would offer is that if you use a proportional font like Times New Roman, you should definitely switch to one space, but if you use a monospaced font like Courier, you can keep on using two spaces if you want to. Your call.