> Basically, the thing is this: I've been thinking about having some of my characters in my stories use swear words from time to time.

It's not always "right" or "wrong". It depends.

Who's the average reader of your stories? Are you targeting a particular age group?

Is appropriate for that particular character?

Is appropriate for that particular story?

Pointless swearing, like some old Italian writers do in their most recent novels - just to show up that they're modern (and, by the way, "the marketing manager asked for some sex and swearing helps to sell some more copies") - is annoying, like all pointless things.
On the other side, if the character needs some realism, maybe swearing is appropriate.

Recently I read a novel from a friend of my father. This friend is a priest here in Milan; his novel tells about the Partisans in Northern Italy and the opposition to the nazi-fascist domination from 1943 to 1945, when U.S. and British armies freed Italy and Europe defeating nazism. His characters are real people, soldiers, communists, most of them hating Christian religion. Just for the note, in that region of Italy, the local idiom uses swearing like punctuation... it's definitely not for the sensible ears!
I had a real, live description of these partisans, their speech, their continuous swearing ... with no swearing at all.
It's a question of style, experience and knowledge of the language.

As far as your Christian feelings are concerned, that's up to you, but in my opinion, saying or writing "damn!" is not all that bad; there are really worse things.

AP.