Selected answers from the Dumb SEO Questions G+ community.
Alan Bleiweiss: You don`t need to. Google will recrawl any pages already indexed. To be fair, if they don`t crawl your pages as fast as you prefer, you can resubmit to Google, it`s just that you don`t need to.
Steve Gerencser: I don`t think I`ve submitted a page for indexing since about `99. It`s just not neccessary.
Jey Pandian: I do it only for a large corporation or household Brand that has a campaign + landing page that needs to be updated ASAP in the SERPs.