Do Blogs Have A Limited Lifespan?

The other day I got to thinking about blogging and if there is ever a time when a blogger should just call it quits. Specifically, I started something of an internal dialogue about what would happen if there comes a time when everything has been said already and any future publications would just be redundant.

I’ll take a hypothetical situation here and expand a little on it.  Let’s suppose that Jane decided to start a blog about cats.  She publishes a few articles a week and covers topics such as feeding, health issues, behavior problems, etc.  Eventually she notices that all her knowledge and experience on this subject has been published on her blog, any related news stories have been covered, and she has nothing new to add.  What now?

Some may say to maybe  revisit older posts and touch on them again.  But even if you do this, how long would you want to continue in the pattern of repeating information that is already on your site?

With the exception of perhaps tech blogs, I am leaning towards the opinion that any topical blog really does have what could be termed as a lifespan.  You may have an incredible blog that is a virtual encyclopedia of information, but eventually your blog will become an exhaustive authority on the subject where nothing new of value can be added.  It would be a bittersweet moment if and when a dedicated blogger reaches this point.

What do you think?  Do you think that a blog can continue to provide new and relevant topical content indefinitely, or do you think that eventually they can become “complete” and maybe should be shelved?