Sunday to Thursday in by nine thirty, anytime weekends as long as I know where you are going. Thats what I would do or rather what I would try to sway the conversation round to with my 18 plus school/college attending child.

Under that age then same time during the week but weekends as long as I know where they are then midnight.

Under fifteen then same during the week and weekend too however sleep overs are allowed as long as I speak to the parent of the other child.