If you are doing a professional SEO audit for a real business, you are going to have to think like a Google Search Quality Rater AND a Google search engineer to provide real long term value to a client.
Google has a LONG list of technical requirements it advises you meet, on top of all the things it tells you NOT to do to optimise your website.
Meeting Google’s technical guidelines is no magic bullet to success – but failing to meet them can impact your rankings in the long run – and the odd technical issue can actually severely impact your entire site if rolled out across multiple pages.
The benefit of adhering to technical guidelines is often a second order benefit.
You don’t get penalised, or filtered, when others do. When others fall, you rise.
Mostly – individual technical issues will not be the reason you have ranking problems, but they still need addressed for any second order benefit they provide.
Conversely, sites that are not marked down are not demoted and so improve in rankings. Sites with higher rankings pick up more organic links, and this process can float a high-quality page quickly to the top of Google.
So – the sensible thing for any webmaster is to NOT give Google ANY reason to DEMOTE a site. Tick all the boxes Google tell you to tick.
I have used this simple (but longer term) strategy to rank on page 1 or thereabouts for ‘SEO’ in the UK over the last few years, and drive 100 thousand relevant organic visitors to this site, every month, to only about 70 pages, without building any links over the last few years (and very much working on it part-time):