Brian, I have a burning question regarding keyword placement and frequency. You wrote: “Use the key in the first 100 words … “. What else? I use Yoast and a WDF*IDF semantic analysis tool to check the content of the top10 rankings. Pretty often I have the feeling I overdo it, although Yoast and WDF/IDF told me I use the focus keyword not often enough.
Many websites rely on other traffic generation methods such as traffic from social media, email, referrals, and direct traffic sources over search engines. For sites like these, SEO errors aren’t as important because search engines aren’t their #1 traffic source. For a smaller website, a couple of errors can have a much bigger negative effect than those same errors on a larger website.
The audit is for all pages and not only one. What happens in the majority of the cases is that pages / posts have similarities so you can group them together. For example the pages of a website may be ok but the blog post pages may be missing titles. It’s a lot of work especially for a 500 pages website but you can start from the most important pages first and work your way to the rest