How often to submit sitemap to Google

You don't need to submit your sitemap to google, if you have an account created on google webmaster tools the first page that is appearing in front after you are logged is:
Dashboard
You can add your website there and the link to your sitemap in xls or html format.
After that if you will visit that account regularly you will see there when Googlebot last visited your page.

Then you will know when to upload your sitemap.

Already done ;) But I noticed in webmaster tools -> sitemap I can choose to resend it. I would like to know if I have to submit it once or every time a page of my site changes.

I resend it every time I make a change :0)

Yes only in one of the cases then if you have something changed in the link structure and you want google to send his crawlers on your website.
Regularly for a good crawler indexing you need to upload also the sitemap, every time when you upload files on the server, I mean the updated files with the changes made on the link structure of your website.

Also in google webmaster tools they give you a security key, you should put that in meta tags on every page of the site.

is it not too spammy? I would submit it every day but I'm afraid google doesn't see it very well.

If you made a legitimate, meaningful change, then no. If you are submitting 1,000 times per day, then yes!

No, no, I add one new page per day and I change the contents of my home page.

Also for these option you have the meta tags that are <meta name="revisit-after" content="1 day"/>, you set there the no of days for the crawler to come again.

There is no spam, as long as you put new content (text, links, etc..).

I think you'll be fine...Like Daniel from Webcams said too, you can add a "revisit" tag, though imho I think it's best to resubmit the sitemap

Make the site map. Put it on the server, and let google Bot find it.. It wont happen any faster by submitting it. And as long as the site map is updated google bot will see it. You dont need to keep submitting it.

Check your server stats and see how many times google bot hits your site in a day. average is between 100 and 2 or 3 K per day.

Google isn't half as stupid as some people sure seem to think it is. Use their webmaster tools, submit it once and watch it - you'll find even months later it comes back to you every month without fail and without you telling it to. Just keep your sitemap updated and if you do make a major change I suppose it's okay to resubmit it, but minus that, you don't need to do anything.

For example, I have not updated the sitemap for my Nina Mercedez site in months. I know, shame on me but i've been so busy with Content Bandit. Well despite my no updates, Google on its own downloaded my sitemap and did its thing on December 1st. Prior to that it had downloaded it like on November 17th, and that's all without me ever touching a thing.

Now my Sunny Leone site, Google downloaded it on December 1st and then again 17 hours ago. That's twice within the first 3 days of the month, with no updates at all on my end mind you. The previous month I got one visit total which was like on around November 5 or around there. I forgot the exact date now.

There is no set rule as to when it will come, just know that it will come and you don't have to keep pressing resubmit to get it to you.

Watching my stats I have found that Google does a quick run by or swipe and sees what is up with my site. If nothing has change it moves on but if I do have changes it seems to register those changes and them comes back later on for a closer, more in depth looks, aka a deep crawl.

Long story short, if you update your website, update your sitemap and Google and other engines will find it and do their thing with it.

Good advice, Pornguy

We will only resend if we add another subdirectory for a girl or section of our site.

never