It seems to be fairly standard to build sitemaps only once per day, usually in the early morning hours. With Google and other search engines going near real time when it comes to indexing and showing the latest content as fast as possible, should we all not be reevaluating how often sitemaps are generated? I think I am going to change mine to every 1 hour on my most active sites.
Google bots might be visiting your site throughout the day crawling but how often are they actually requesting the sitemap files?
Not sure. Most addons that create sitemaps ping the search engine letting them know there is an update.
If you have a Google Analytics account configured to point to your sitemap it should say in there, if my memory serves correctly at the moment on a Monday, the last time it was retrieved.
I just checked because I was curious since it has been a bit since I've been in there (I don't have XF generating sitemaps so I haven't added one for some time). It is actually in Google Webmasters (https://www.google.com/webmasters) -- After verifying your site URL you'll see a "Crawl" link on the left sidebar menu where you can view the crawl stats & sitemap info for your site.
I'm still trying to get my sitemaps fixed; installed vbSEO sitemap mod and I can't point to the sitemaps. xD Once a day seems enough for me. My content doesn't get updated that quickly.
