Hyphens, En Dashes, Em Dashes

Q. When does one use hyphenation to break words? I already looked at the Manual and still have some questions. I have heard that when the text has a jagged right edge no hyphens should occur and when text is justified it is allowed. What about magazines, leaflets, fliers, catalogs? Can one be more liberal in these and if so is there some guideline on this?

A. These are mostly aesthetic judgments that we leave to a designer’s specification. Different publications might have different tolerances, depending on the look the designer wants to effect. Hyphenation is often necessary in ragged right justification (see CMOS 7.47: “Though hyphens are necessary far more often in justified text, word breaks may be needed in material with a ragged right-hand margin to avoid exceedingly uneven lines”). And Chicago specifications call for no more than three consecutive hyphens.