I’ve been the bearer of bad news to a lot of people lately. You don’t need to overwork your thumb anymore and hit the space bar twice after a period. Just once. And people are having a really hard time with this. They never got the memo. So here it is.
Re: Your right thumb is tired
There is no longer a need for the double space after a period. Modern fonts take care of the spacing for you.
It’s the typewriter’s fault, with it’s monospaced type, that you learned to double space in the first place. Every character on a typewriter occupied the same amount of horizontal space – the m and the i had the same size block, which left words looking loose. Therefore the double space was the norm for defining where a new sentence began. Modern technology (well, anything since the electric typewriter) uses proportional typesetting, in which skinny characters are given less space than the fatter ones. No longer do the m and the i occupy the same amount of horizontal space.
The double space after a period is no longer needed. Your right thumb will thank you.
Type professionals everywhere
When asking Google what is correct, there are many people that find both sides of this debate to be correct. One of the most compelling references I found was this…
Williams 2003. pp. 13–14. This refers to professionally published works, as it is possible for individual authors to publish works through desktop publishing systems. Williams states, “I guarantee this: never in your life have you read professionally set text printed since 1942 that used two spaces after each period.” See also, Felici 2003. p. 81; Strizver 2010; Weiderkehr 2009; Williams 1995. p. 4.
At the end of the day, it’s your decision if you want to single or double space after a period. But now that you’ve officially received the memo, you can at least start trying to give your right thumb a break.