Hyphens are really important for clarity and should be used regularly; close attention to hyphen use is critically important (as they create the difference in meaning be “a man eating chicken” and a “man-eating chicken”). Hyphens connect descriptive words and numbers and they clarify the use of common prefixes. If you only ever learn the rules of five punctuation marks, make sure that hyphens are in your top five.
Hyphen difficult ranking: 3/14 (somewhat difficult to master)
Hyphens are widely misused or forgotten by many day-to-day writers, but they are critically important for clarity. There are seven rules for using hyphens, making them one of the more complex punctuation marks, but this is one you’ll want to make sure you have a strong grasp of.