As you may be aware, that Google is monitoring over time how often you update your pages and add content to it. Google is monitoring the stability of site update as one factor for search engine page ranking. In order to update the content of your blog, all you have to do is to post, and post again.
Perhaps, when it comes for the time where you have no ideas what to write for your next blog post, you are trying hard to find topic for it. In your head, it's about maintaining better position and increase search engine page ranking for your blog.
This morning I came across to Blogherald.com for an article by Lorelle Van Fossen about tips to update and revitalize old blog posts to increase search engine page rank. It got me thinking about the possibility to revisit my old blog posts and rewrite it.
When you have no idea for a new blog post, rewriting the old blog post become a good solution. It doesn't mean that you just pull them and post it as is. What you can do is by making a new title that is more proper for current situation, fix and update information on it, some factual information at that time maybe not factual enough at present, fix the typos and more. Updating some links and remove the dead links, you know that Google is also hates dead links, so is your readers.
It is also mentioned, that giving a new perspective to the old posts and rewrite it with more better search terms keywords play in helping your blog got found by the search engine. Which is mean, traffic, and search engine page ranking.