Not the eighteen most important things you could test. The smallest set whose passing gives you enough confidence to ship — which is a different and more useful question.
Forty-five minutes, because a pre-release suite that takes two days gets skipped by the third release.
Eighteen checks, about forty-five minutes, no tooling beyond a browser and something that can send an HTTP request.
Eighteen checks, about forty-five minutes, no tooling beyond a browser and something that can send an HTTP request.
Eighteen checks, about forty-five minutes, no tooling beyond a browser and something that can send an HTTP request.
Eighteen checks, about forty-five minutes, no tooling beyond a browser and something that can send an HTTP request.
Because they are more useful passed on than kept, and because a checklist that finds something in your own product is the only honest argument for the full case bank.
Each one is eighteen cases out of ninety-plus. If it finds a defect, the rest of them are where you look next.
Each demo runs five of the checks against a simulated system, in your browser. Watch a defect fire, flip one switch, and watch the same check pass. Nothing to install, no email.