The rules when I was a teenager were...
No curfew, just when I could drive a phone call screaming "where are you, why aren't you home?" (after asking for a time to be in and being told "I don't mind, whenever.")
Friends could come round whenever and GIRLS could stay over, no questions asked. My little sis could have boyfriends stay over from about 14.
I could call my mother from about 12-13 and tell her I was staying out, no I didn't need anything bringing, that was fine. No checking up or even asking where I was. Which is good because it was usually at a boy's house!
The one time I did stay over after a mixed party with alcohol it was at a girl's house and my mother decided to scream down the phone that I was lying and she knew I was going to go to my boyf's house and have sex... OK, I was 19, but no I wasn't doing that!
We didn't have any clearing up rules, but I did it anyway. Of course I missed something and was very rude, lazy and ungrateful because I never did anything. Every other mother thought we were great for our level of cleanliness after our parties!
The rules I would have liked would have been
A loose curfew (as many of the others have suggested).
Being asked where I was.
Knowing what level of "tidy" was appropriate.
Not screaming at me that I was having sex and lying when I said otherwise.
TV off by X time (not told off next day that it was "disappointing" we were watching films at 3am).
Whatever age boys can stay over at have it the same for when the others hit that age. Don't say that it's OK for one at 14 but not another at 16, or 17, 18 or 21... or in fact until less than a year before her wedding.
HTH.

