Offline, I will say here that I have never ever said any foul language out loud. It's just something that's not necessary. With over half a million words in the English dictionary, aren't there better words you could be using instead of a select twenty or so? Online, however, I will swear quite often in my typings. I'm pretty sure everyone on the Discord knows about that, ehehe.
Working in customer service and maintaining a good online reputation has made my filter go way way up in the past few years. I rarely swear unless I'm incredibly frustrated (or if I stub my toe XD) though if I am I usually grit my teeth behind the smile until I get home where I just groan into a pillow for an hour or so XD When it comes to touchy subjects I don't usually hop in on the conversation unless I really know the people. I have my opinions but don't really voice them because in today's world people scrutinize that stuff under an electron microscope.
Online, I swear a fair bit if it's allowed. But offline, it really depends on who I'm talking to. If it's with someone I've known for a while, I'm more lax on my filter, but around new people (and especially at my job) my vocab is just pure and clean.
Around my house, with my younger siblings around, I choose my words very carefully. I let my shields down slightly when they're asleep and my parents are in the room, but I will admit that with my friends at school I swear often, but not as bad as my friends since I'm used to being around my siblings or my parents.
I don't really use one that much. Unless it's around my sister. But besides that, any conversation is good conversation by me. I used to filter. But nowadays, that doesn't win you many kudos in the friends or relationships department. I do filter in terms of what I wear a lot. But that's something else.
I've found that the opposite tends to be the case - either the filter limits the kind of people you can be friends with, or generally people don't care about the language you tend to use. In my experience, the latter tends to be the most common. I've never known or heard of anybody who would require another person to swear in order to be considered.