By 12 - 14 months, DD1 wasn't sleeping during the day at all. We found that if she did, she would be up until 11pm! And then sleep until about 2am in her own room, then in with us until about 8am. She would get tired at around 4pm so we would let her chill out then with a movie or ABC for Kids at that point (TV wasn't on during the day otherwise). She's now 4 and if she happens to fall asleep during the day (usually it's in the car after a big day), she still follows the same pattern and is awake until really late.

DD2 is 13 months old and has been a shocker of a sleeper. She will only nap once during the day but is usually in bed between 8-9pm.