When you are making sitemap.xml file in any tool, it will ask you how you want to set “change frequency”. If you look at sitemap documentation, you will see that you should add that line for every URL, too.
So, what is “Change frequency” in XML sitemap?
“Change frequency” is planned frequency particular web page will be updated with new content. Tag for that is < changefreq >. It can be set to: daily, weekly, monthly or yearly.
Of course you can’t be sure what frequency pages pr posts will be updated but you can guess. And don’t try to trick Google to visit your website more often by placing “daily” on every entry. It will see you are not updating pages daily and will not trust you anymore. 🙂 Anyway, Google’s John Mueller said 4 years ago:
Priority and change frequency doesn’t really play that much of a role with Sitemaps anymore.John Mueller
And if you have big sitemap.xml file and you want to know how many URL’s are listed in it, you are free to use our free Sitemap URL counter tool.