Before you decide to delete a page, consider whether someone out there may have that page bookmarked or linked to, or that a search engine may have that page indexed. Once you think about that you may re-think your decision to delete it! Maybe it would just be better to set the page to not display in your navigation. Then the page will still exist if someone gets to it from somewhere out on the web, but a viewer won't be able to navigate to it through your site's navigation.
Of course, if your page has obsolete content, and the page URL has become obsolete, then you will want to delete the page from your site.