DD 16, often has friends both male and female over, sometimes doing homework or just chatting. We were finding there seemed to be no particular time some friends would go home, which seemed odd to us! We've put rules in place that friends must leave by 9pm weekdays so DD is in bed at 10pm and 11pm on Fridays and Saturdays, which to be fair DD accepted and stuck to. Does this seem reasonable? What do other mumsnetters do, do you have rules on this?