It is important to choose the “style” of DJ you want for your wedding reception. You need to find out what kinds of events your DJ is most used to performing. Many disc jockeys are not exclusive wedding professionals and will attempt to market themselves to any type of event that offers opportunity such as graduations, proms, reunions, the club scene, etc., and then book a random wedding reception as it comes along.
You need to ask the right questions of your DJ when shopping for a wedding reception. The type of DJ that plays primarily in bars and clubs may have all the top-hit charting songs that you can bump and grind the night away to but what about for your family, friends, children, and grandparents? Is the music age appropriate or least edited for content? Does your DJ have music to span across decades so that everyone will be pleased overall? If the club scene is a majority of their work then they will be used to a different style of audience than what you have attending your reception. Therefore, you should make sure at the bare minimum that the DJ has a basic understanding of wedding etiquette, experience in coordinating the entire evening of events, and the ability to effectively communicate and coordinate with the other various wedding professionals. (i.e. photographers, banquet managers, wedding coordinators)
Here is to your reception planning success!

