Is it worth the time to go back and optimize old blog post (adding keywords, H1, H2 Tags etc) from a year ago?

Selected answers from the Dumb SEO Questions Facebook & G+ community.

• 
  Carter Lamere: Quick SEO question. Is it worth the time to go back and optimize old blog post (adding keywords, H1,H2 Tags etc) from a year ago, will that help with my SEO? Or is it a waste of time?
• 
  Saijo George: If the title is not h1 , switch it over. Certainly will make a big impact
• 
  Ranu Jain: Yes Carter, Google's search results are dominated by old sites. An older page that’s regularly updated may outperform a newer page.
  
  You can re-optimize your old content to increase traffic to your site. Doing an effective keyword research is by far the most important step. Once you have the final keywords, insert them into the older post.
• 
  Harry Dance: I agree with +Ranu Jain ;but I appreciate this could be a lengthy process, maybe just optimize the most unique/ your favourite posts. There is no harm attracting visitors to posts which you feel could benefit someone easily
  
  A great example of this is an ex client who created a blog post in 2011, around tilling on wooden flooring . This used to get over 500 visitors a month.
• 
  Greg Kristan: This is a video that might help +Carter Lamere ;
  http://moz.com/blog/how-to-move-rankings-up-on-older-existing-content-whiteboard-friday
• 
  Carter Lamere: Everyone has been a great help, very much appreciate the answers!
• 
  Dave Elliott: updates of tags and stuff is bound to help, but it also might be worth your time updating the articles if anything(or your opinions) has changed since you wrote it.