Fresh Content = Frequent Indexing
Google Loves Frequent Updates
More Content, More Keywords
Fresh Content Increases Your Authority Potential
Keep Your Audience Informed and Updated
Yes content updation is the most important terms in SEO you need to update content on your blogging sites also you need to make some editing of your old content like 3-4 months content make these content refresh this will gives you the best result in search Engine ranking.
I think keep website content always unique.
Content updation can increase your rank in SERP