Content modification on website helps or not


We all know that content is the king for a website. Can anybody suggest me the about content modification.

please let me know, content modification for a website would help or not. Can I use this thing for websites.


Help with what?

Help regarding to stay visitors on the website and improvement in the ranking in the Search Engines.

Modification in what way?

You may want to post an example people could suggest changes to in the Content Review section.

My site is related to automobiles. I am asking suggestion about as my content is very old on my pages, there are no keyword density.

So if i frequently updates my content only theme related of that page and improve my keyword density, then this frequently content modification would help the website in search engines, for visitors or not.