Let’s face it, no one wants to make several changes to the same portion of a web page when you have static information/pages. Enter php include(). If you have a common header, footer, block of information that needs to be on multiple pages and the thought of only editting something once instead of on multiple pages, php include is for you! (assuming you have php installed on your server)
To include a common header:
(you would place this statement in your code wherver you would like your header to be located)
Once you make a change to header.html, all pages that have the include statement will be updated. One file, one update, several pages updated.
On sites that have several static pages, I try to use as many include statements as possible for common elements so that I can spend more time on development and not having to worry about updating hundreds of pages every time something needs to be changed.