With many points of grammar and style in English, it’s fairly easy to detect a trend if you read enough texts by educated native speakers with good writing skills. This isn’t the case, however, with the hyphen, so I thought I’d offer a few comments in case people are confused.
Generally, when phrase is run together to make an adjective before a noun, it’s hyphenated, but it isn’t when it follows the noun. So you have an ‘up-to-date guide to consumer law’ but would say that ‘my guide to consumer law is up to date’. However, an exception to this is that it’s not considered good form to hyphenate a phrase including an adverb ending in ‘–ly’. Thus, you’d say ‘this is a badly written guide to consumer law’ but that ‘the same author produced a well-written guide to commercial contracts last year’.
With compound nouns, the more progressive trend seems to be to use one word where possible, so this is generally what I advise. I’d therefore say ‘guidebook’, ‘email’, ‘website’, ‘paywall’ and so on rather than hyphenating (or even using two words). This mirrors a process where words like downstairs used to be written as down-stairs, a practice that looks very quaint these days.
A few other situations where using a hyphen is recommended are:
- when using non-, cross-, re- when followed by an ‘e’, as in non-lawyers, cross-reference and re-entry
- nouns from verbs like mark-up, pay-off, trade-off, crowding-out
- when forming compounds involving numbers or dates, e.g. late-2009, the mid-1990s, one-off, second best
