When adding links to a page, do not hardcode links from within your site. Instead, use the Link List option within the WYSIWYG editor (under Insert > Insert/Edit Link). This will ensure that if the link location changes, it will update automatically.
From the Link List you can link to:
PRO-TIP: Avoid inserting “monkpreview” links into URL fields or they will not update when your site goes live, or when the page title or navigation location changes.