META Name Expire
The expires Meta tag declares to search engines when the content on your website will expire. The expires Meta tag defines the expiration date and time of the document being indexed.
The expires tag is commonly used in conjunction with the Revisit Tag as a means to get search engines to re-visit a website every few days. This is commonly used by websites who update their content frequently and want search engines to have a fresh copy of their content.
If you replace or rename a webpage please use a 301 refer to point the search engines in the right direction. Search engines will automatically replace the old page with the new page.
This meta tag has almost no influence on your search engine ranking.
You may add this Expires meta tag to all of your webpages, so not only in the first index page. Make sure that on every page relevant meta tags are added.