I have not got to that stage yet but for me after I graduated my mom set a curfew of midnight and if I wasn't going to be home before that I was supposed to call and let her know where I would be. I think that setting a time that you are comfortable with but giving the option of being able to call and say hey I am staying at so and so's house is a good idea. This may also be something that you could discuss with your child and maybe you could both make the decision so everybody feels like they are a part of the decision making.