According to the Old Testament the true test of a prophet is where they lead you, not their level of accuracy. It is the same in the New Testament. A false prophet might be accurate, but they lead you away from Christ and into sin. Paul said we see as through a glass darkly. You can't discount a person's gift for imperfection any more than someone can discount you for making one mistake along the way; but you can judge which way a prophet is pointing, and you can judge the fruit of a person's overall life.