Overview
Web users, especially users with disabilities, depend on web pages being predictable. If navigation is consistent from page to page within a website, this makes it much easier for screen reader users, screen magnification users, and others to find particular items within the navigation.
Techniques
Use menus and other navigational mechanisms consistently across all web pages within a website. Be sure menus appear in approximately the same place on each page, with items repeated in the same relative order across pages.
In addition, any links, buttons, images, or other components that are used repeatedly throughout a website should be labeled consistently. For example, if a web application includes a “Sign In” link on some pages, and a “Log In” link on other pages, this can lead to confusion as screen reader users familiar with the “Sign In” link might try to search for that on pages where labeled differently, and would come up empty-handed.
Most Details from this page were gleaned from the University of Washington's Accessible Technology section.