We’re living in a fast-paced world, and we tend to jam a lot of things together. We even make up words like hangry, J-Lo and whatev.

Words that begin with prefixes — take, for example, “redo” — are the result of us getting our point across faster. After all, it’s faster to say “redo” than “do it over again.”

But in writing, not all prefixes are created equal. Here are some tips on when you need to hyphenate prefixes, according to the AP Stylebook:

  • In general, don’t hyphenate with a word that starts with a consonant.
  • Use a hyphen if the prefix and the word that follows begin with the same vowel, like “re-enter.” (Notable exceptions: “cooperate” and “coordinate.”)
  • Use a hyphen if the word that follows is capitalized.
  • Avoid double vowels and triple consonants: “anti-intellectual,” “pre-empt,” “shell-like.”

—Sarah Muench