This plugin SHOULD be included in the WordPress code base. There is no reason NOT to have this plugin. It proactively resolves many potential problems with permalinks, changing permalink structure, and incorrect search engine indexing of permalinks. There was a time (up until about 15 minutes ago) that if a sitemap was submitted to Google with a few thousand incorrect permalinks and you resubmitted it correctly, it could still take DAYS to crawl those bad links, give you a huge report of crawl errors to resolve and then finally index the correct ones that you submitted immediately after. Now, everything in between is eliminated. From what I've seen so far, I could submit a sitemap with ANY permalink structure, change the structure on my site to something ENTIRELY different, and this plugin will not only prevent me from getting crawl errors, but will allow the correct page to be indexed and/or send the user to the correct page, almost magically. Before this plugin, a broken link could sit on page one of a search result for weeks and be useless to me. Now, there is no such thing as a broken link. I LOVE this plugin. It's a MUST have!