A hyphen "icon" embedded in your text - indicates either that a hyphen is called for at that point, or (if you have a hyphen there already) that the hyphen is not appropriate. We hope that this page will explain why.
Although smart word-processors seem to have taken over the job of hyphenating broken words at the right-hand end of our lines and spellcheckers can review our use of hyphens in other places, these technological marvels are by no means infallible. Microsoft Word, for example, flags as misspelled almost any word with an unhyphenated prefix: antidiscrimination and cogeneration, for example, are marked as misspelled words and re-sign, co-bra, ever-green, and be-loved are marked as correctly hyphenated words by that software.* Generally, it is a good idea not to use justified text in academic papers; that will cut down on a lot of decisions about hyphenating. The APA Publication Manual, in fact, insists that you not break words at line-endings in any case, but that can lead to lines that are too brief and aesthetically unbalanced.
The rules for hyphenating at line endings are so complicated that no one can be expected to keep track of them. If you're ever in a situation where you have to hyphenate at line-breaks, go to a dictionaryunless you can explain why you would break experience between the e and the r, that is, and then you can do whatever you want. Remember that if you adjust one line-break for aesthetic reasons, that may well affect subsequent line-breaks in the text.
Probably the best reference text for these decisions (next to looking up everything in a dictionary, that is) is The Chicago Manual of Style. An excellent online resource on hyphen use is the Editing Workshop by Sonia Jaffe Robbins at New York University. Tom Little voices a dissenting opinion in "The Great Hyphenation Hoax," which seeks to free writers of the innumerable rules and imponderable tables of the Chicago Manual of Style.
Hyphens have other uses
There is no space between a hyphen and the character on either side of it.
With a series of nearly identical compounds, we sometimes delay the final term of the final term until the last instance, allowing the hyphen to act as a kind of place holder, as in
Be careful not to overuse this feature of the hyphen; readers have to wait until that final instance to know what you're talking about, and that can be annoying.
*These software hyphenation problems were pointed out by Howard L. Marshall of Laveen, Arizona