Does Google reprocesses submitted sitemaps from time to time?

Question

Assuming one submits a sitemap for a website in Google Webmaster, does Google reprocess it from time to time? If yes, at which rate?

Answer 1

Edit: Google will recrawl it (see comment by John Mueller from Google below).

However, if you want your sitemap reprocessed more quickly by Google, the recommended practice is to resubmit it.

You can resubmit using Webmaster Tools or using an HTTP request.

Using Webmaster Tools:

1. On the Webmaster Tools Home page, click the site you want.
2. Under Optimization, click Sitemaps.
3. Select the Sitemap(s) you want to resubmit, and then click the Resubmit Sitemap button.

Source: http://support.google.com/webmasters/bin/answer.py?hl=en&answer=183669

The linked source also describes the slightly more complex alternative method where you use an HTTP request.