We have worked with several clients whose previous designers left them with a "black box," a website with no documentation on the site or about the hosting, leaving the clients in a bind when updates are needed and the designer has moved on. At the conclusion of each of our projects, we provide written documentation, clearly describing how the site is organized, with a list of photos and scripts used on each page, and other useful details. In addition, we document the underlying code so that every page is "legible."
Although we would like all of our clients to stay with us, we understand that changes occur. If you work with another designer in the future or want to make updates yourself, you can use this documentation as a road map; we firmly believe that the wheel should not be re-invented.