Comment by bccdee

I've turned against them, partly because they're too flexible. Many of the things a dash does can be done better by more specific forms of punctuation like semicolons, colons, or brackets, which give your sentence a clearer visual structure.

It's also easy to get too used to dashes and start sticking them in places where they don't belong. If you're using a coordinate conjunction like "and" or "but," a dash is awkward and redundant. "A period is great to express a complete thought — and it shifts the register of the next letter," can more easily be "a complete thought, and it shifts" or "a complete thought — it shifts."

Dashes take up a lot of space. Like exclamation points, they draw the eye. Does the eye really need to be drawn to "a complete thought; it shifts"? If you let them, dashes will replace all your other punctuation marks, and your writing will become a soup of horizontal lines. Dashes are a sometimes food.