Site maps are navigation for our web site and they are generally written in XML. Site maps makes our web page search engine friendly.The search engine crawlers first search for the site map to find the internal pages of a web site.
Regular submission is a good thing... as long as you have something new to submit. Don't submit the same sitemap twice. Wait until something new happens on your site (add page, remove page), then update your sitemaps and ping them again.
No need to submit regularly to google. crawlers indexes sitemap and all web pages periodically & update their data.
I don't even submit my sitemap that often. Maybe once or twice a month, but definitely not after every update. I like Google to find my pages organically and index them, which is where internet marketing and social networks come into play.