Now that you have the XML sitemap module properly installed and configured, you can start defining the priority of the content on your site—by default, the priority is .5. However, there are times when you may want Google to visit some content more often and other times when you may not want your content in the sitemap at all (like the comment or contact us submission forms).
Each node now has an XML sitemap section that looks like the following screenshot:
You can adjust the priority on a node-by-node basis by changing the default. You can even omit nodes from the sitemap by selecting Not in site map.