Hyphen or not?

Our lesson today, class, is about when and when not to hyphenate phrases.

Hyphenate adjective phrases. You can have set-up instructions, a step-by-step plan, a last-minute trip, living-room furniture, and out-of-the-box thinking. All these phrases are adjectives. They describe nouns (technically the word should be the more generic term “substantives,” not “nouns.” “Thinking” isn’t a noun, it’s a gerund.)

Do not hyphenate phrasal verbs or prepositional phrases. You sign up for a trip, set up a process, hook up a connection, sign in to your account. You can put down the box,  and you can pull over to the side of the road (verbs), you plan step by step, go on a trip at the last minute, keep it under your hat, and you think out of the box (prepositional phrases).

Some phrases are used as nouns. “That was a nasty put-down.”

One type of exception to these hyphenations: Some phrases have become so common they have turned into compound words. You have a pickup truck, a login ID, and a nice setup.

Can you think up some better examples? Put your own thought-of phrases in the comments.