The way I was raised amounted to 'it isn't ladylike to swear. If you do, people won't respect you'. Do I swear? Yes, sometimes, but I try not to overdo it.
I think there are a few angles when it comes to swearing that make a difference. I feel it's something you should have control over and its use should be a matter of choice, not 'accidental'. This amounts to its use at appropriate and useful times, but not because you don't know better/can't help it around certain situations/company. If you don't exercise control in its use, it can be seen as lower class or a sign of weakness, but almost everybody swears to some level and it's more common in some places/among some cultures and people than others.
If it's something you say all the time, it can lose its effectiveness and meaning. It becomes 'the way you talk', whereas if you don't normally swear, it adds more to your words or writing.
There are some people who look down on it, and some people who identify with it, and some people who like it. When I was a kid I was told 'don't listen to music with swearing in it and don't talk to people who do'. Music has changed quite a bit and so has the perception of these things. There's an element of going along with the status quo or not when it comes to profanity too, though depending on the situation, either swearing or not could go either way.
I just swear sometimes, and in some company. Hairy gets to hear it a lot. If I'm out, I avoid any and all swearing, especially around kids.