Q. CMOS 10.39 says this: “Where space restrictions require that the names of months be abbreviated, one of the following systems is often used.” How do you suggest one defines “space restrictions”?

A. Tables can be a challenge to format; abbreviations are generally useful there. And in footnotes and bibliographies and other places where sources are cited, abbreviations are customary for certain commonly used words, though Chicago doesn’t require them for months (some styles, however, do). Outside of those contexts, abbreviations are usually unnecessary—that is, until you run out of space (e.g., in the running heads for a printed book).