I aim for a largely PG13 effect in my characters, but I’m trying to get them to be a bit more gritty. Like ‘bugger a bunny’ or the occasional F word. I’m thinking occasional means that in a novel it would occur about every third chapter or six to eight times in the entire novel. That’s, I think, a good ratio.
But I’m open to opinions, and if you are suggestive, please say why. How often?