Do I need to submit the sitemap to search engines everytime it is updated?

Question

If I have a sitemap_index.xml:

http://www.domain.com/sitemap.xml 2010-09-28

And I change the content or update the page, and then change the lastmod, will I then have to submit it again to the search engines, for example in google webmaster tools (the section where you submit sitemaps)?

Thanks

Answer 1

As long as you've told Google about the sitemap, they'll check it periodically. The more often it changes, the more they'll tend to check it.

If you go to Site configuration | Sitemaps, it'll tell you the last date they downloaded your sitemap.

Answer 2

No. It is however worth taking a look at the sitemaps page on webmaster tools every now and then and seeing if any errors were reported with the sitemap.

Answer 3

@Skilldrick is right! Also, google states that the results are not effected by the sitemaps anyway. They should only give a guidance to the search spider. He/she will make the final decision!!