One, two, even three spaces after a period?
Please stop putting two spaces after a period! I beg you. Unless you’re using a manual typewriter. Then and only then should you use two spaces after a period.
There was a time in history—the time of the typewriter—where two spaces after a period had a useful purpose. But, technology has improved and as much as we hate change, we need to change with it. We no longer use typewriters and therefore no longer need that extra space.
Let me explain: typewriters use what is called monospacing. Monospaced type means that the letter “i” which is obviously quite narrow, uses the same amount of space as the letter “w” which is significantly wider. This is because the typewriter isn’t advanced enough to know what letter the user is typing so it must leave enough space to accommodate any letter.
Because of this, monospaced type has awkward horizontal white space between letters which makes it difficult to see where one sentence ends and the next begins. Thus, the advent of the two-space rule.
So, unless you’re pecking away at a manual typewriter or using one of the few monospaced fonts left in usage (Courier) please stop! For the love of your designer.