When to take the GMAT

Hi,
I am hoping to enter graduate school in the Fall of 2014.
Schools I am interested in applying to have application deadlines of approx. January 10 for early deadline and March 31 for final deadline.

Does anyone have advice on when I should take the GMAT? I am thinking October or November of 2013 or as late as mid December 2013.

Any advice or experiences would be helpful.

Thanks!