I use the f-bomb more frequently than I should, but meh. I do clean up my language around small kids (under 10), but if they're older, they get the "use this word at your own risk. I'm not responsible for you getting in trouble using it" spiel. I also use "frag" when I can't use any notable variation of "fuck" (like at work.) My mom still shoots me a dirty look if I use it more than once an hour, but I've grown immune to those. I won't use any variation of any swear in front of grandparents though. One "Jesus forgives you" half hour speech for using "FRAK" when I dropped something on my toe was enough for me.
If I swore growing up, I get soap or dirt in my mouth. That or "EXCUSE ME?!" I didn't start swearing until I left for college, so I think I'm in canio's "making up for lost time" camp, there.