Pretty good question really. I had thought two at one time. But then back in the day, I was using a word processor. And it became a well-used habit to type with two. But then one begins to regularly use computers and not so much anymore. I use one now as I stick with Times New Roman. Fact is this question amuses me because I still have manuscripts on the back burner with two spaces in them. Mostly because it is a hard habit to break and it was really quite recently that I got my brain to get my fingers to comply with it. Now that I AM used to it when I do work on those manuscripts I have to correct this as it annoys me that each work I have is not the same format.
Way back in the day, I took Typing along with Computers in school and in Typing that is where you learn the two spaces after the period gig. Also, learn to type with more than four fingers but while I type very fast I still do not type in the method I learned. Mind you, I do have some nerve damage in one hand so that makes it a little tricky to feel the keyboard the same way. Luckily I know where everything is. Some instinct for where the keys are and randomly using whatever fingers I please apparently. No rhyme or reason to it anymore. Chaos method. Unlike my spouse who apparently still has yet to figure out where those letters are and has to carefully locate each one and plunk at them so methodically. Until I do it for him. Which I think is his devious plan, to begin with.
Obsolete as the rule is now it stuck around for many years in formal manuscripts requests for traditional publishers as I recall. You assume they desire it for whatever random reasons they design for those rules they come up with. That is when I was sending out manuscripts. Maybe that has changed as well. I honestly don’t recall the last time I sent out one. Before the markets went to hell for sure. So I guess it has been a little bit. Nevertheless, if a publisher wants two spaces then that is a real bitch to put back in there. Just as much of a bitch to get back to one space certainly. That is the one thing I have not figured out how to ‘Replace All’ on. Perhaps there is a method for that. There really should be.
– Q: My writing course instructor insists that I should go back through my novel manuscript and use only one space after periods instead of two spaces. I was taught that it was always a double space after period. Is she wrong or am I just a dinosaur?—Anonymous
The “two spaces after period” rule was instituted during the days of typewriters. Typewriters had only one font, so all the letters were monospaced, or took up the same amount of space. That means that the skinny “l” and wider “w” occupied the same amount of space on paper. To make reading easier, the two-space rule was born to give the eyes a break between sentences.
With the dawn of computers, word processing programs not only began offering an absurd number of fonts, but each font was programmed to space characters proportionally (“l” takes up about a third of the space “w” does). In turn, most computer fonts will automatically give you enough room between sentences with one space. So, as a rule of thumb, use just one space when typing up your manuscript on a computer.
There are a couple of exceptions—the fonts Courier and Monaco are still monospaced—but it’s better to stick with one space and switch fonts to Times New Roman or Arial rather than use two spaces. (How many spaces after a period? )