XML Sitemaps

Do you guys use XML site maps to help with the indexing of your sites, also, does it provide adequate gains in your seo efforts?

Yes, it's recommended to have one whether you do seo or not.

It helps make your site organized and all pages noticed by search engines. It neither guarantees everything would be indexed, nor does it help with your serps.

Sitemaps are a way to tell Google about pages on your site we might not otherwise discover. In its simplest terms, an XML Sitemap—usually called Sitemap, with a capital S—is a list of the pages on your website. Creating and submitting a Sitemap helps make sure that Google knows about all the pages on your site, including URLs that may not be discoverable by Google's normal crawling process.

yep, for sure it is good to have a sitemap. it doesn't help much in SEO, but mainly for discovering and indexing all your pages