The most important thing I've learned is that every (good) typeface is designed for a specific reason, otherwise they would have used an existing one. That reas

The most important thing I've learned is that every (good) typeface is designed for a specific reason, otherwise they would have used an existing one. That reason may be overcoming a technical limitation of the time, or there is a quality in the content that needs additional emphasis. All of the great typefaces have some kind of history. An original use case (the brief), influences, designer biography, etc. - which can be looked up on wikipedia or elsewhere. As a general rule, if your project meets the original requirements of the typeface, it should be appropriate. Sometimes a face will pick up additional cultural connotations along the way, depending where it's used. And great graphic designers know when they can mix-and-match history for style.