Selected answers from the Dumb SEO Questions G+ community.
Neil Cheesman: This sums it up... Generally, hyphenate two or more words when they come before a noun they modify and act as a single idea. Perhaps Middle class... and middle-class Class A, B & C - B is the `middle class` Being middle-class is a `class` of economic wealth (perhaps) So, use hyphens when you should... imho
Neil Cheesman: ps maybe use something like an online grammar checker?
Neil Cheesman: "When you use kws in your copy, should they be with or without hyphens or a combination of both?" You use the grammatically correct word whether it is a keyword or not - although some hyphenated words can be either - in which case it is probably wise to use both but I would suggest a minor point in terms of seo. imho
Michelle Korn: I`m asking about what the people are searching for.
Most people (unless they are writers) don`t hyphen the words.
Neil Cheesman: From my perspective IF a word such as `sugar-free` is commonly used as hyphenated in written text (although not necessarily by people that type into search engines) then that term should be used on the web page... ie search for "sugar free juice" and the top websites will likely have (more of) the term sugar-free on them...
Shane Lowry: Google reads Middle class and middle-class as the same