She's Never Dealt with a Crisis
On the day of your wedding, you should be focused on your hair, makeup, gown and all of that till-death-do-you-part business. Wedding planners are there to handle any last-minute crises that pop up.
A top-notch planner will finesse any situation, from too-short tux hems to wilted floral arrangements, while keeping the bride's stress level down as low as possible. When interviewing a potential planner, be sure to ask her for examples of such last-minute issues and how she handled them. Her response should provide a clear picture of her ability to cover your bases on your big day.