What will it tell you? How will it help?

[fomayof928@mowline]

Is the mobile version of the website "optimized" and crawlable? Are all header response codes and tags set up correctly, and so on, on both versions? Is important textual content missing, or hidden, in the mobile version?

Why Equality Audits Can Save Your Butt
The last thing you want to do is diagnose a major traffic drop on D-day when things go mobile-first. Even if you don't change anything right away, cataloging the differences between site versions will help diagnose issues if/when the time comes.

This can also help you improve your rankings right away.

I know a great team of SEOs for a large brand who cyprus number data oblivious for months to the fact that their entire mobile site (millions of pages) had title tags that all read the same: “Brand Name - Mobile Site.” They found this flaw and contacted us to look more fully at the differences between the two sites. Here are some other things we found:

There was a bug at the template level in a page type on the mobile site that was causing rel=canonical tags to break, but only on mobile, and in a way that gave Google conflicting instructions, depending on whether they served the page as mobile or desktop. The same could happen with any tag on the page, including robots meta instructions. It could also happen with HTTP header responses.
The mobile site has less than half the amount of navigation links in the footer. How will this affect the flow of PageRank to key pages in a mobile-first world?
There are far more relevant products on the product detail pages on the mobile site. Again, how will this affect page rank flow, or even crawl depth, when Google goes mobile first?