Get the biggest SEO Bang for the buck. Meta tags are very effective SEO Tools since this is the first means that will inform the web bots as to what the page is about (after reading the url path). Owing to that Meta tags are derived from the content of the web page it stands to reason that every web page's Meta tags is different.
While there are numerous Meta tags the Title Meta tag and the Description Meta tag receive priority. Google discontinued the use of the Keyword Meta tag as they were much misused.