It is very important to submit your website to Google so that it can index all of your pages.
First, check if your site is being crawled by Google bot and you can do this using the Google Webmaster Tools, I suggest you become familiar with these tools.
Second, check how many pages are in Google's index by typing in the Google's search box the following:
site:www.yourdomain.com (replace "yourdomain" with your domain name)
Third, get a sitemap ...there are many tools to generate XML format sitemaps, check with a programmer to find a solution and generate this sitemap automatically as you add more pages to your website.
In my opinion, there's no need to submit many times your website to Google, just check the crawl rate and you should be fine.
Cheers 