Before I give a longer and more detailed answer, feel free to check out my SEO Auditor tool here: http://www.youthnoise.com/free-seo-audit.
Give it a try and learn crucial SEO data points affecting your website.
And remember, there’s no perfect on-site audit tool.
Google’s guidelines are not established. They have a rock-solid algorithm, but they keep that information close to the best and away from the general public.
The Value of Using Auditing Tools
Since Google doesn’t tell people exactly how to optimize their sites, be aware that each and every SEO auditing tool provides estimations of what is believed Google wants, within the framework of how that particular SEO and developer saw it.
While this information can be helpful, there’s also a lot of junk data out there.
These auditors are arbitrarily grading different metrics, looking at page speeds, meta-titles, duplicates, various technical details like internal linking, the number of pages on the site, the number of words per page, and keyword density.
Ultimately, auditing tools will look at everything that we’ve mentioned and more in some cases. After analyzing all of these data points, they will provide random scores. These scores won’t mean much to you if you don’t know what they represent.
Website Optimization Per Business Model?
Whether you own a local business, a nationwide business, an e-commerce site, or an SAAS, your website optimization needs to be different for each business model.
I’ve yet to come across an SEO audit tool that asks, “What is your business model?”, and then specifically audits for that type of business.
This type of auditing tool doesn’t exist. Somebody should probably build it. But the fact is these SEO metrics change all the time and it might not be practical to create an auditing tool this comprehensive.
On-Site Optimization & The 80/20 Rule
It’s the 80/20 rule when it comes to on-site optimization.
You can spend hours of your time and tons of your SEO budget making everything absolutely perfect according to some random auditing tool, or you can just focus on the 20% that matters the most on your website and move on other aspects of SEO that also matter.
Some examples include: offsite SEO (i.e. backlink building) and content creation.
I really hope this helps. If you have any other questions, please feel free to follow up here.