To me it's more of a situational habit. Many years ago when I used to work in construction, swearing was so common place that it just became part of your regular conversation. The problem came at the end of the day when I left the work site it was hard to shut that off and my mom got mad at me several times for my foul mouth. Even today when I'm in with a group of people who swear a lot, I'll pick up on that and then later at home my wife will comment on my language. A lot of times I just don't realize I'm doing it. I don't know what to do about it other then getting in the habit of thinking about what you say before you say it, which can be a lot harder then it sounds. However it's probably a good habit to get into even for people who don't swear a lot. Just take a breath, count to 5, and think about what you're going to say before you say it.