What counts as "finishing a period"?

I was talking to a friend of mine who will b TTC from feb, and we got talking about when we "finish" a period....she counts hers ending from the day she stops bleeding but continues to have the brown discharge....where as I wait til I have no brown discharge and that's where mine "finished"! So I'm curious to know...where every1 else "finishes"?? And should I change my way of charting my start and end dates?!?!