I like swearing. Swearing can be rude, funny, sexy and insulting. Day-to-day I swear a lot, but in my writing I don't.
When spoken, a well deployed swear word can be effective, but in writing profanity has lost it's power. We've all seen so many of books with F*ck in their title that it no longer delivery any shock value. The fashion brand FCUK was once provocative, but not anymore. We've seen it so much, that when we read a curse in a novel, it doesn't surprise us, it feels forced. Swearing takes the reader out of the story - the opposite of what we want to achieve.
Spoken swear words are incredibly versatile (the Polish kurwa is truly gymnastic), but this versatility undermines their utility in fiction.
"Fuck!"
What is this character saying? What do they feel? Are they angry, shocked, horny, in pain? Without context, we simply don't know. The swear word takes up space on the page and communicates nothing to the reader. If I find myself writing swear words, I try to replace them with an expression that better serves the scene.
When absent, profanity is not missed. No one ever finished a novel they enjoyed and complained that there were not any swear words. Also, some people don't like swearing. A reader may have enjoyed your book, but because it included swear words, they won't re-read it and they won't recommend it to their friends. You won't lose readers by omitting profanity, but you may lose them by including it.
There are exceptions of course. If you're writing erotica, using fuck, cunt, and dick may be appropriate and in line with readers expectations. An unexpected curse from a character known for their propriety may emphasise their stress, but only if you've set up the false-expectation.
If you need a swear word, consider censoring it. In Mort, Terry Pratchett makes a joke that simply wouldn't work without the implied profanity.
“Well, ----me,” he said. “A----ing wizard. I hate----ing wizards!”
“You shouldn’t----them, then,” muttered one of his henchmen, effortlessly pronouncing a row of dashes.”
This is funny, but made funnier still with censorship.
I swear a lot. I like it. I enjoy it. If you meet me, expect it! But in my fiction writing, I don't. You may feel differently, and that's ok, but for me swear words rarely earn a place in my work.