I have a classifieds site, so normally 100 posts will come a day. So what should be the ideal sitemap change frequency ? I am using a free service to create sitemap, so the links are limited in the sitemap. (500ns) is there any free sitemap creater for unlimited URLs? Oce i saw 300 URLs indexed in google webmaster tool, but once i change the sitemap, what i was able to see that number reduced to 100. (i thnk old URL's could have been replaced from sitemap. Please share your openion.