Consistency is important for web site accessibility and usability. WCAG 2.0
Success Criterion
3.2.3 (Level AA) requires that navigation elements that are repeated on web
pages do not change order across pages. Success Criterion
3.2.4 (Level AA) requires that elements that have the same functionality
across multiple web pages be consistently identified. For example, a search box
at the top of the site should always appear in the same place and be labeled the
same way.