Automated audits find maybe a third of real problems. The rest are found by listening. A screen reader on your own page for ten minutes finds more than a linter with a perfect score.
About 1 min of reading
Run the six checks on one page
Tab walk
Before you run it, say out loud what it will print. Then open the answer.
Screen reader on one task
Before you run it, say out loud what it will print. Then open the answer.
Zoom and CSS off
Before you run it, say out loud what it will print. Then open the answer.
Record the findings
Before you run it, say out loud what it will print. Then open the answer.
Tab walk, screen reader on one task, 200 percent zoom, CSS off, reduced motion on, high contrast mode on. Six checks, all under two minutes.
Treat a clean linter report as necessary, not sufficient. It proves nothing about names that are technically present but useless, or about traps and ghosts.
Turn on the OS screen reader and go through one task end to end. Note where you hear nothing, where you hear a filename, and where you cannot tell where you are.
At 200 percent text zoom, nothing may clip or overlap. A layout that breaks at 200 percent is a failure even if it looks fine at 100.
With CSS disabled the page must still be readable and in a sensible order. This is a one-second check that catches order bugs no linter reports.
Each one is defined here on this site. Open the entry for the full definition and the other words it points at.