A blog can never be finished. There is always content to be added, different ways to look at the same thing, inviting people to do guest posts, and making sure your blog ranks well with Google. Even the best blogs will lose their traffic if they are not updated properly. A blog cannot be finished because blogs are designed to inform your visitors while possible selling some products or showing ads so that you get some kind of commission. Blogs are never finished, and that is the magic of a blog.