How often should you submit your site to search engines? Once? Once every month? Everytime I update the site?
I don't remember when I submitted my site to search engines. You don't need search engine submissions nowadays. Just get some good backlinks and you will be automatically indexed.
Once submit is enough. Because if you too often to submit on search engine, your URL is marked as spam.
Never, always let them find you. An easy way is to create a rss feed for your site/blog/page and submit to digg or stumbleupon and that all you should need to do. You can also take your rss feed url and post on pingomatic.com. Then there is always the old fashioned way....write a couple of articles and submit them to article directories. Not only do articles get you indexed but they deliver quality targeted traffic as well.
once, if only the site is ready or if somehow i have restructured the whole site content then i resubmit it once again
The question "how often" should not be said. Because you can only submit your sites to search engines once or never (depending on your backlinks). If you submitted your sites often, they might mark your site as a spam.
Its best not to submit your site to search engines instead build links and make the SE find you I never used submission
Only first time, then, let these SEO Bots will find you. But keep updating your site with quality articles submissions, leave comment ob blogs and all, will keep you update automatically.
YEs they will find you , i made a site that i did not submit 1 day later it was in google. it had backlinks form other site do