When a person has a Website; Should they have a metatag just for the index page or should they have them in many pages.
You need metatags in all the pages. But I would not bother to use more than the description meta tag. Forget about the rest. They are not important at all any more.
I try and put a strong call to action into the descrption tag making sure that keywords cross match to the body text. I also still add my keywords to the keyword tag again making sure they cross match to the body text. Not sure this has any value anymore but it takes a couple of seconds and might be worth it in the future who knows. The description still has a role to play as it sometimes is used as the SERPs snipet. Although I am not sure when and why.