Most technical SEO is triage, not optimisation
Technical SEO gets sold as a long list of improvements. In practice it is mostly about not being broken. A site that is crawlable, indexable, unique and usable on a phone has cleared the bar that most competitors trip over.
The list below is ordered by consequence. The first four can remove you from search results entirely. The rest are worth doing and will not save you if the first four are wrong.
Tier one: the four that break everything
- Crawlability. Check robots.txt does not block what you want indexed. A disallow line copied from staging is the most common catastrophic error in this field.
- Indexability. Check meta robots and headers on real pages, not in theory. A noindex left over from a rebuild is the second most common.
- Canonicalisation. One URL per piece of content. Watch for parameters, trailing slashes, http and https, and www and non-www all serving the same thing.
- Mobile usability. Indexing is mobile-first. If your mobile rendering hides content, that content is effectively gone.
Tier two: the ones with real but bounded impact
- Site structure. Every important page reachable within three clicks of the homepage.
- Internal linking. Genuinely the most underused lever most sites have — relevant links with descriptive text between related pages.
- XML sitemap. Current, accurate, no 404s or redirects in it.
- Page speed on real devices, particularly layout stability.
- Structured data where it fits: organisation, article, FAQ, product. Correct, not decorative.
Tier three: worth doing, rarely decisive
Image alt text, heading hierarchy, breadcrumbs, hreflang for genuinely multilingual sites, and open graph tags for how links look when shared. All good practice. None will rescue a site with a tier-one problem, and none will make a thin page rank.
If someone proposes a six-month technical programme without having checked the four tier-one items in week one, ask why.
The audit rhythm that prevents surprises
Once a quarter, spend an hour: crawl the site, check index coverage, confirm robots directives, and compare landing-page traffic against the previous quarter to catch quiet declines.
After every deployment that touches templates, routing or hosting, check indexability. Most catastrophic SEO incidents are deployment accidents, not algorithm changes, and they are visible within a day if anyone looks.
What technical work cannot fix
A technically flawless site with nothing worth reading will not rank. If your pages do not answer the question better than the ones currently ranking, no amount of schema will change the outcome.
That is worth saying plainly because technical work is measurable and content work is not, which makes it tempting to keep doing the measurable thing long past the point of usefulness.