Vendors tell me that they offer discounts to professional coordinators for a number of reasons. When there is a Wedding Coordinator, there will be fewer phone calls to their businesses, they have one person to coordinate with instead of trying to reach a busy bride, or deal with multiple friends and family members. They know that someone is going to be present for deliveries at a time that is convenient for them and is going to keep a protective eye on their equipment.
At the wedding itself, vendors only have to concentrate on what they were hired to do. So many times a DJ or a photographer end up adding to their duties things that a coordinator would do but without a picture of the event as it has developed over a longer period of time. Coordinators can communicate with the vendors to help keep things on a schedule or informing them of changes that are going to have to be made due to key people arriving late and mishaps that are just going to happen because life still happens even if it is a wedding day. A Wedding Coordinator is there to keep all of them informed of anything that might effect the timeline which has been developed with all of the vendors in mind. I hear from vendors all the time that their job is made so much easier when a Wedding Coordinator is present.
I don't only work with vendors that give discounts, because many vendors have a great product or talent as well as great pricing. I enjoy being able to pass on discounts to clients from vendors because it can sometimes make the difference in them getting the wedding they've dreamed of as compared to one they feel they have had to settle for. Clients consistently say that they were reluctant to hire a Wedding Coordinator, but later say hiring a coordinator was one of the best decisions they made.
Wishing you the greatest of days!