Dollar for dollar: hyphens? [closed]
Solution 1:
You are correct in both instances.
In your first example "Dollar for dollar" is a phrase. No issues there.
In you second example, you're using the phrase "dollar for dollar" as an adjective. In this case, you have what's appropriately called a "phrasal adjective". (Or sometimes a "hyphenated adjective" or even a "hyphenated phrasal adjective".)
When a phrasal adjective precedes a noun, it usually takes a hyphen or, for phrases of three or more words, hyphens. This makes things easier for your reader and helps prevent miscues.
(Grammarist)
So yes, when you use a phrase as an adjective, your phrase-as-an-adjective usage should be hyphenated.