How can I automatically close blog posts to new comments after a period of time?

When a blog post has been published for a while, you may no longer be interested in people adding comments. If you would like this to be done automatically then you can choose after how many days it should be closed.

This can be changed by going to the Comments workflow settings category and changing the Automatically close to new comments after setting to the required number of days. If you later reopen the post to comments it will not be automatically closed again.