Setting up the permalinks structure is one of the first things I do after installing WordPress. It takes less than 5 minutes but setting up correct permalinks structure can improve your blog rankings. Permalinks is something that plays a huge role in the search engine rankings. I’m currently using %postname% permalinks structure, which works very well. http://www.wpkube.com/what-is-the-best-permalinks-structure-for-wordpress/ I'd love to hear your thoughts on this.
I doubt that changing your permalink structure can improve your rankings. URL has only slight SEO effect. The best structure is probably %postname% because users know what to expect when they hover their mouse over a link and see its URL.
I agree with Devtard - the best permalinks structure is /%postname%/ - I'm using in on all my WP websites.