Grammar Repair Shop: Hyphenate a non?

Are you supposed to use a hyphen when you add “non” to a word, i.e., non-verified or nonverified. My grammar books say no hyphen, but I often see it spelled with a hyphen. We use the word “nonpayment” in a lot of our correspondence. Should it be non-payment?
— Anonymous reader

It depends on whom you ask. Stylebooks and dictionaries are not in complete agreement on this one.

Most of the time, though, dictionaries and editors close the gap. So, for example, you would write “nonpayment” rather than “non-payment.”

One exception to that rule: If the “non” comes before a proper noun, a hyphen is usually best. Example: “non-U.S. citizen.”