Selected answers from the Dumb SEO Questions G+ community.
Alan Bleiweiss: Do you mean your domain name registration expiration date? Or do you mean the individual page Meta "expires" tag? I
f you mean the latter, the answer is why would you communicate to search engines "this page is going to expire"? Some people use it in conjunction with the Meta "refresh" tag, in an attempt to artificially get search crawlers to revisit a page based on some frequency they think will help them improve SEO visibility.
Whether this actually helps or not is something I have not ever once seen proof of either way. Others may have more direct experience.
What I will say is this though: I would prefer to not attempt to artificially force Google to do anything. Instead, if I want more frequent crawling then I need to work on ensuring I consistently add new high quality pages, and consistently work to build site value and trust signals. Then I can more confidently leave it to Google to determine crawl frequency. If they come to a page and it really hasn`t changed, why would their system give your site more trust?
Casey Markee: The short answer is no, domain registration length/expiration doesn`t affect SEO. As far back as 2009 Google`s John Mueller and Matt Cutts` both have said on the record that this is not the case.
Instead of me linking to all those statements, Brian Reich has a good article covering the history of this whole topic here:
Now, that being said it`s never a good idea to wait to the last minute to renew a domain because that`s bad for you and users. Further, it`s resulted in a ton of hilarious examples in history you would want to avoid, like these examples:
Steve Gerencser: Can we make a list, a very long list, of all the things people have said were ranking factors that aren`t?
Michael Martinez: If you only have 20 days until the domain expires just renew it.
Loren Baker: It`s important if you DON`T renew your domain ;)
Suraj Gadage: Doesn`t matter to Google. Just renew it to keep you site functioning.