How many weeks can you go over your due date?
It depends on the situation. My second child ended up ten days late (I was induced) because the doctor did not feel there was enough amniotic fluid around the baby. And sure enough, when they broke my water hardly a trickle came out. But she was completely healthy. It also depends on how the mother's doing. if her vitals are getting bad, they will induce earlier.
I asked my OB that hen pregnant with my last child, not that I was worried my first came 3 months early, but I was interested and he told me, that after a certain time, there is no benefit to the baby to remain in the womb. I've heard of women going a month over. A long as the baby is not in distress, it can remain in the womb until either it goes into distress, it gets too big to deliver vaginallly, or the mother and dr. decide there is no extra benefit for the baby and let's do it today. Yay! MOdern technology.
'full term' is 40 weeks, but can go to 42 weeks. if nothing is happening by then, chances are they will induce labour.