I'm a big fan of no curfew for teens, so that they can learn by trial and error how to live their lives (aka how much sleep they need to wake up on time, get themselves to school, do the HW, etc.) NOW in highschool, rather than just be "let loose" in college with no life skills, or have to learn by getting fired at work for oversleeping / not having projects completed, or end up in the brig for being late in the military. It's FAR better, imho, to miss first period or even sleep till noon or later and have an unexcused absence in highschool than the far more expensive alternative of doing it in college, on the job, or in the military. There is a LOT more latitude / wiggle room to learn in highschool than once they turn 18 and move out. The parallell is that we don't "catch" our children every time they stumble as toddlers, but for some reason most parents bend over backwards to keep them from learning their own balancing points as teens.
Of course, hand in hand with not having a curfew is ALSO living responsibly with those who love them. Meaning that they need to come and go without waking other people up, calling or leaving a note on a regular basis, etc. If my husband just "didn't show up" after work without a call, or came in and woke everyone up, etc... well anyone can see that those things don't fly. It's about respect, not control.