META Name Revisit After
To make a spider revisit your site after a certain amount of time , you can do that by REVISIT-AFTER Meta-tag. This meta tag is used by several North American search engines.
To much or to little spidering of your website is not good. So if you upload new content to your website every week, keep the number of days around 7. Google doesn't use this Meta tag; they have their own internal date.
<meta name="revisit-after" content="period">
You may add this revisit-after 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. Add keywords and phrases that are relevant and correspond to the text and the language on that specific page.