My current WIP has a fair bit of profanity. I never planned it this way. It's just that I've been working hard to be true to these characters and not sugar-coat their dialogue. I've never really thought the profanity would end up being a problem because most of the YA authors I would hope to emulate use it in their writing in the same way.
I was interested to learn during a recent read-through of my draft that the eff-word is much more prevalent in the chapters that were completed earlier in the project than those that are more recent. Interesting! It's almost like the more I've gotten to know some of the characters, the less they've been cussing.