Generally how long do you have to play at the Atlantic City casinos before you can get Complimentary rooms?

I only play poker too...the main thing is make sure you get your card swiped as soon as you enter the poker room...the only casino so far that has given me comp rooms is to Hilton (I've used them twice)...and I play mostly tournaments and some cash games...I know you don't get as much points for tournaments but I guess it added up some how :)