Dance for children ... how much is too much??

So I recently enrolled my girls in dance classes. Overall, they like it. We did however only enroll them in two classes. Some moms have their children in four or more classes. At what age can they handle such a rigorous schedule?

01
    03/16/14
    Tessa
    I think that one extra curricular activity is enough until highschool.
    1
    About Magen
    Birth: December 31
    On Moms.com since: Sep 14, 2013