I've spent 24 years teaching teenagers, 15 with middle schoolers. The biggest mistake I see parents make is nagging their teenagers to death. You have to pick your battles carefully. Is this really worth fighting about? A lot of it isn't. Kids do need boundaries and they need to learn to respect boundaries, but allow them some space. Not enough to hang themselves with, but enough to explore their teenagerness. Try not to micromanage them. Treat them with respect and believe it or not, you'll get respect back. Yell at them, hover over them, lecture them, and you've lost the battle. Learn to talk to them; it's different than when they were in elementary school. They need consequences, but they need to logical, natural consequences. Fairness is BIG on a teenagers list.