The tab 'publish' in the document's content menu can be used in order to define a time frame during which the document is active. This is helpful when using different versions. See Versions & Status
Production Start Date
If set, the version will turn productive at this date.
Production End Date
If set, the version will turn offline at this date.
Comments concerning this element. This information is only visible for other editors. It will not appear on the generated pages.