I think it depends on a number of factors such as age, relationship to you, gender, how serious the issue was, and how long you've known the person. I generally give family members more chances than I would anyone else, and it's not that many.
With friends, I generally give them two chances. With the first one, I will give them the benefit of the doubt and assume it was unintentional. If there is another one, I tend to distance myself from that person all together.