title: Django signals vs. overriding save method
body: <p>I'm having trouble wrapping my head around this.  Right now I have some models that looks kind of like this:</p>
  
  <pre><code> def Review(models.Model)
      ...fields...
      overall_score = models.FloatField(blank=True)
  
  def Score(models.Model)
      review = models.ForeignKey(Review)
      question = models.TextField()
      grade = models.IntegerField()
  </code></pre>
  
  <p>A Review is has several "scores", the overall_score is the average of the scores.  When a review or a score is saved, I need to recalculate the overall_score average.  Right now I'm using a overridden save method.  Would there be any benefits to using Django's signal dispatcher?</p>