If you're unsure whether a hyphen is needed, check an online dictionary or paste the phrase into Google and check common usage. Short dashes ( – ) are more commonly called "en" dashes, because they ...

Writers can misuse or overuse hyphens, em dashes, colons and, to some editors' disgust, semicolons. Using a period is a simple solution.

For consistency in University writing do not include spaces. An em dash is the width of the letter "m" in the font and type size being used, and should never be used in place of an en dash or hyphen.