with the sleeping 10+ hours, i don't think there is any age that I would say they do that at, my 5 year old gets in bed at 7pm asleepby 730pm and she is normally awake at around 6 she just sits on her bed and plays. Even if we keep her up she still wakes at 6.

When you asked earlier in you thread how do other parents managae dinner time with a baby that wakes around that time. I put my dd in my back in an ergo and cook with her there, also usually have her there while showering the other two and doing things with them otherwise would never get stuff done.