Hyphens, En Dashes, Em Dashes

Q. A coeditor and I have a difference of opinion with regard to the following as it relates to “spare use” of hyphens. I maintain that hyphens are necessary because both words together modify the noun that follows. My coeditor thinks they aren’t needed. Can you settle the debate? Here are some examples: “IBM-based software” or “IBM based software” “End-user documentation” or “end user documentation”

A. Yes, I would use hyphens in both of your examples. Otherwise the first phrase could be taken as a noun-verb-object clause, and in the second phrase “end” could be read as a verb. We don’t object to hyphens, but rather avoid a proliferation of unneeded hyphens—it’s more a house aesthetic than a rule. One bugbear is the hyphenation of an entire descriptive passage: “He loved to use the throwing-the-baby-out-with-the-bath-water metaphor.” In this example, the writer could either put quotation marks around the metaphor or rephrase entirely.