This message is for you if you’re still putting two spaces between sentences. Consider this an intervention. We love you, but the time has come to move on. I understand that your high school typing teacher told you to ALWAYS put two spaces after a period and between sentences, but those days are long gone. The time has come to put one and only one space between each sentence — and this is a message of love.
Much has been written about the many reasons why — reasons that go way back into the history of printing, monospace vs. proportional spacing, all sorts of deep design reasons and the difference between a typewriter and a computer keyboard. A quick Google search will lead you to all the information you need to know about the art and science behind one space over two.
The bottom line is, the times have changed, and this is not an issue to fall on your sword over. No matter how long you’ve been putting two spaces between sentences, changing the habit is easier than you would think. Give it a try. Embrace the new. Change is good for your brain.