It's sort of strange, when you think about it. I can see why an author might want to refrain from using certain vulgarities. If the author is religious and has convictions against those sort of words; if the author writes for tweens or even teens; if the author writes in certain time settings (think Regency period) where swearing was some serious hankie dropping business.
But I have to admit, my first thought about that question was, "Hell yes, my characters swear."
I'm not going to throw a side-eye at any author who refuses (for whatever reason) to make their characters swear. I will give a major side-eye, however, to any completed novel that has modern adults say stuff like, "That stinks" unironically. There is a line called realism. If you cross that line, no matter how pure your intentions, you've made a big error in the land of fiction writing. (To be clear, the line goes both ways. Don't make the mistake of thinking you can signal character traits like TEEN or THUG or HEARTLESS BUSINESS MAN just by tossing some vulgarities into their dialogue. I mean, who are you, E.L. James writing about currency changes in China?*)
For the record, it is entirely possible to write a novel with realistic characters in a modern setting and not have any of them swear. That's what I set out to do with my last manuscript, JAYMA RODGERS GOES TO COLLEGE, since I knew I was going to be submitting it to LDS publishers. That being said ... had Jayma and her friends been hunting down a serial killer, involved in a car crash, lost their jobs, or had any other high-stress, high-drama moment come their way ... I'm not sure I could say the same. JRGTC was a romantic comedy set in college, and while there is conflict, it's more of the "mixed romantic messages," "loneliness," "failed chemistry tests," and "existential angst of being in college and not knowing what you're doing" variety. In other words, it's slice-of-life kind of stuff.
My current project is a bit heavier, and accordingly, the characters swear. It's a part of their teenage, dealing-with-drama-beyond-that-should-have-been-beyond-their-maturity-level thang. (Oh mygosh, I am so old. Thang.)
Do I feel bad about it? Hell, no. (The cursing, not the-being-old.)
That being said ... I think no matter what kind of character I wrote, there are certain things I just wouldn't have them say, words I consider far more offensive than any technical swear could be. (This is me, getting off my high horse.) So I suppose everyone has a line in the sand. Except Stephen King, because I'm pretty sure there's nothing that man won't write, and man, I love him for it.
Writers, where is your "line"? Do you have one? And readers, what is the most egregious example of non-realistic dialogue you've ever encountered? (Either of the vulgar/attempting to avoid being vulgar, or the "this clause modifies the provisos!"* variety?)
Finally, I leave you with this thought, dear Blog friends, from a cherished film from my childhood:
"He worked in profanity the way other artists might work in oils or clay. It was his true medium; a master."
-Ralphie, A Christmas Story
* For those of you who haven't had the pleasure of reading 50 Shades of Grey, Ms. James characterizes her 27-year-old bazillionaire Christian Grey by having him shout nonsense into the phone like, "I don't care about currency changes in China, damnit!" and "The remaining subclauses of this clause are to be read subject to this proviso and the clauses above! Ugh, gosh, why is everyone so much dumber than me?"
So. Yeah. I still do not know what Christian Grey's company does. Though, to be fair, Christian's lady-love Ana (a college graduate and an English major) responds to all of it with "Holy crap!" and "Jeez."
Ahem. Let that sink in for a second.
The realism thing cuts in a lot of different directions.