The best of the skinny
Once you submit your blog to Google, you are not supposed to resubmit it and you can just update your sitemap. You can also install the sitemap plugin for automatically keeping your sitemap up to date. Apart from that, the sitemap plugins also keep on reporting Google regarding the changes on your website. You can also use blogging software for the generation of sitemaps. However, if you are not using this software then you can create sitemap on your own with the help of tools offered by Google for creating sitemaps.