I've never had a swearing habit until recently. (Note: swearing habit in my world is very different than what you may be thinking.)
The word "damn" started flirting with the border of my vocabulary a few months ago. Every week or so he'd come in for the sake of entertainment, gradually becoming a more regular sight. He'd vacation there for days at a time, mostly just out at night, timidly, with the lower end of society. The vacations became frequent enough that he started looking at getting a permanent place set up. He grew more comfortable and confident, shopping in the nicer stores, associating with more prominent members of the community. Bought a house. Planted a flower garden in front. A vegetable garden in back.
I'm okay with it. I wouldn't dream of saying "damn" in front of my family or select other associates; he'll always know he's an immigrant. But he's established and comes in handy frequently enough that he's welcome.