When does helping turn into habit?

Since the girls were born, I've been adamant that I didn't want them to depend on one thing to fall asleep; having me in the room or singing laying in bed with her, and part of it is that I wont fit into her bed lol.  I'm just as adamant now, but it's a little hard to walk that fine line between doing it to help her and it's becoming a habit for her.  There's been times where she'll say she's scared, but I can tell it's just a ploy for her to stay up longer.  But some days it's really hard to tell if she's actually scared or it being a ploy.  Tonight was hard because it took an hour to keep her in bed.  She wanted me to sing to her 5 different times, she was "scared" about 6 times, she wanted to come sit by me once, and she used Kensi as an excuse twice.  I blame the last few nights on the time change.  She's been essentially going to bed at 7p and I'm sure her body isn't quite tired yet.  So what do I do?  Do I sit in the room when she wants?  Do I sing 5 times if she wants me to?  It's a damn fine line, and walking it is really hard!