If you are developing big web sites with parts of the web pages having repetitive content, you absolutely must use Server Side Includes(SSI). Notice in this site all the sections have the same header, site search and left menu. If we were to make a change any of these areas we would have to manually change it in all the pages or if we were using templates or libraries we would have to FTP all the pages every time we make a change. As we are using Includes we need to make the change only in the Include and it automatically gets reflected in all the sites that are using that Include. Best of all it reduces our FTP time by more than 200% as we only need to FTP one file and not all the pages using the Include (If you are familiar with using templates and libraries you will know that though using templates and libraries cuts down your development time a lot you still have to FTP all the files that use the library or template. This is not the case when using SSI's).