Risky Business

Sometimes when I interview people, they are fond of cursing. They do so out of passion for the subject of which they are speaking or out of habit. My journalism professors have told us to just take out the four letter words unless we feel the word is ABSOLUTELY necessary to add life to a story. On the other hand, my English professors (esp. my creative writing professor) was fine, even encouraged, the use of curses. In short, what is the general rule about using obscenities? Are there set ways to spell certain words, i.e. f*#!ing v. f*#!in' v. some other way, or is it at the discretion of the writer and editor?