Your special event "dream team" -ie. photographer, videographer, band, dj, planner, are going to spend countless hours on their feet the day of your event in order to meet and exceed your expectations. Therefore, it is important to remember to give them a chance to "refuel" during your event with a meal and a drink (nonalcoholic, of course).
According to Liene Stevens of Blue Orchid Designs, "a good rule of thumb is to provide a meal for anyone who will be at your event over a meal hour or for longer than five hours." Remember, your event may run from 7pm until midnight but your photographer might starting shooting at 4 in the afternoon. (That makes for a very long day.)
Some vendors may outline meal requirements in their contracts but others may not. Even if you are not contractually obligated to provide meals, it is a very nice courtesy which should not be overlooked. Vendor meals can be simple - sandwiches, chips, fruit & soda, but keep in mind that your venue/caterer will most likely charge you a bit more than your local deli. Often vendor meals can be served in a separate area near your event space allowing your team to take a quick, mutually agreed upon break.
Communication is the key to a successful relationship with yor Dream Team. If you have an event planner, she will handle most of the communication regarding your event, including small details like vendor meals, with your other team members. If you don't have an event planner, be sure to let your team know in advance where and when their meals will be served. Also, be sure to find out exactly how many "assistants" each team member will have on-site. If you take care of conveying these details before your event, you eliminate a cause for stress the day of your event.