While a DJ will provide music for a wedding for about 4-5 hours they will also need time for set up and breakdown. They will most likely work 8-12 hours on the day of your wedding. Moreover, that time may or may not include the drive time to your venue. Thus, it is a long day for any professional wedding DJ. Because they come with so much gear they are often the first to arrive at a venue for set up and the last to breakdown for the night.