Hyphens, En Dashes, Em Dashes

Q. Is word-for-word hyphenated? Is side-by-side hyphenated?

A. They are both hyphenated only as adjectives and only before a word that they modify: A word-for-word reading. The reading was word for word. There were side-by-side mirrors. The mirrors were placed side by side. (See also CMOS 7.96, section 2, under “phrases, adjectival” and “phrases, adverbial.”)

[This answer relies on the 17th edition of CMOS (2017) unless otherwise noted.]