Examples are often easier to understand than rules, so let's start with a few of those. These hyphens are all correct:
-A do-it-yourself kit
-A technology-based solution
-A lily-lined basket
-A wish-you-were-here postcard
-A 6-year-old boy
-A 20-percent discount
-The end-user experience
These are all examples of compound modifiers. In other words, multiple words together ("compound") modify (or describe) a final word. You can usually hear the rhythm: BLAH-BLAH-BLAH blah, DA-DA-DA da. They feel like they go together. So if you write by instinct or ear and feel fuzzy on grammar and punctuation, I suggest listening for this rhythm as your first guidepost. Then clarify your thinking with a few easy principles, which I'll explain in a bit.
Also correct but confusing:
-I will make a follow-up call.
-I will call to follow up with him.
-I will handle the follow-up.
Same words, different hyphen usage. Bummer, huh? Why the inconsistency? Here's where we talk about Frankenstein. I'll warn you now: It's a little gory.
Think of "parts of speech" as body parts -- arms, legs, nose, etc., rather than nouns, verbs and prepositions.
Notice the "body parts" in the examples above:
- follow up -- verb + preposition
- follow-up call -- as above but "follow-up" is glued together with a hyphen and used as an adjective modifying call
- follow-up -- verb + preposition used to make a noun
Why this matters: You don't need a hyphen when the words are being used as their natural selves -- as in, a verb used as a verb rather than forced into service as an adjective.
The Frankenstein analogy refers to putting together disparate "body parts" to create a new whole. It's unnatural. When you do something unnatural, you need glue to hold it all together. (This sounds goofy in the real world, I know, but it's a good memory tip, so ...)
Hyphens are glue. They hold together Frankenstein words, which are words forced into unnatural service as something other than their natural parts of speech.
So if you "call to follow up," you are using "follow" as a verb, which it is, and "up" as a preposition, which it is. Nothing unnatural. No hyphen.
But if you "make a follow-up call," you are forcing the verb and preposition into an unnatural new role as an adjective modifying call. This is a Frankenstein word. You need glue (a hyphen).
Let's look again at the first set of examples. To get rid of the hyphens, you need to use words as their natural parts of speech:
- a kit that lets you do it yourself
- a solution based on technology
- a basket lined with lilies
- the boy is 6 years old
- the experience of the end user
There are two exceptions to the compound-modifier rule, but I will save those until the very end of this post.
Now you know most of what you need to know about compound modifiers. And now you realize that your "hyphen" question is really a "compound modifier" question. But there's another situation where hyphens turn up, and luckily the Frankenstein and glue metaphors apply there, too.
Here's Part 2: hyphenated nouns. When you put two words together to make a new noun, they become a Frankenstein word, so you need glue (a hyphen). In "I will handle the follow-up," we've turned "follow" and "up" into a noun, even though -- when taken separately -- the parts are actually a verb and a preposition.
Eventually over time, some hyphens go away. It's hard to keep up with which words have gone over to the other side. So I suggest checking http://www.m-w.com/ whenever you wonder if a word is one word, two words or hyphenated. The AP Stylebook is usually in agreement.
Examples of words people often think are hyphenated but aren't:
- end user (two words)
That last one is tricky, though, right? Now you know that it's not hyphenated as a noun but that would be if you turned it into a compound modifier: end-user experience.
Hyphens are glue. You need them for Frankenstein words. Your first clue that you might be looking at a compound modifier may be the rhythm: two things modifying a third, three things modifying a fourth, DA-DA-DA da.
Now for the exceptions to the compound-modifier rule:
(1) Ly-adverbs never take a hyphen (which makes sense because the adverb remains an adverb) -- centrally located knob, specially designed interface, wholly owned subsidiary.
(2) Proper nouns never take a hyphen -- Jordan branded handheld, Web hosted application, Cincinnati based headquarters
A final word: A dash is not a hyphen, and a hyphen is not a dash. They are not interchangeable. A dash -- the long version of a hyphen or two hyphens together -- is scissors. Scissors cut things apart. Dashes can sometimes replace commas, as I've done two sentences above this one in blue. Dashes, as scissors, cut apart the parenthetical explanation from the rest of the sentence.
I could say more about the dash, but let's leave that for another post.
For now, just remember:
(1) Compound modifiers take hyphens unless they involve a proper noun or an "-ly" adverb.
(2) To find out if a noun is hyphenated, look it up in the AP Stylebook first and, if it's not there, look in up at http://www.m-w.com/.