The usage of hyphen after “re” (which means once more here) used to confuse me. Is it “redo” or “re-do”? “re-iterate” or “reiterate”? “re-enact” or “reenact”?
I found this gem in the New Oxford American Dictionary (used by the Dictionary.app in my Mac):
USAGE
In modern English, the tendency is for words formed with prefixes
such as re- to be unhyphenated: reacquaint, reconsider, reshape. For
the sake of clarity, however, hyphenation is sometimes favored when
the the root word begins with a vowel: re-erect, for instance, may be
preferred as a less awkward spelling than reerect. A hyphen is often
used when the word formed with the prefix would be identical in form
with, but different in meaning and pronunciation from, an already
existing word: re-cover (meaning ‘cover again,’ as in: we decided to
re-cover the dining-room chairs), as opposed to recover (meaning ‘get
better in health’).