Johnson l Don't Go Mad; Hyphens can be tricky, but they need not drive you crazy. Economist, June 10, 2017.
Quote:
" 'Today' overtook 'to-day' in frequency around 1926 in America, according to data from Google Books, and a lit later than that in Britain.
"English is a Germanic language that allows for many different kinds of compounds, including those made from two adjectives ('blue-green'), two nouns ('kitchen sink'), adjective-noun ('dark-room'), noun-adjective ('slate-blue') and so on. But which ones should be written separately, which hyphenated and which closed up ['email' as opposed to 'e-mail' preferred by The Economist].