By Judy Vorfeld
When should we use quotation marks for fairly common expressions and figures of speech, including slang? (A figure of speech is a word or phrase such as a metaphor, simile, hyperbole , or personification, according to Wikipedia.)
Quotation marks are rarely needed for common expressions, says Chicago Manual of Style 16 (7.57). The only time we need to use them might be for phrases borrowed verbatim from another context (environment, setting) or for terms used ironically.
Writers often use “Scare quotes” (7.55) to let the reader know that a term is used in a nonstandard or special sense. CMS recommends using them rarely, as overuse can irritate the reader.
Note on works of philosophy: sometimes in such works, the writer uses single quotation marks for special effect, but CMS discourages its use because it usually confuses the reader.