A short trial should test the part that is genuinely uncertain.

Trials are only useful when aimed at the actual doubt. A week of a new tool that you spend setting it up, a class where the first session is introductions, a trial subscription used on a quiet fortnight: all of these end with the question unanswered, because the thing you were unsure about never got exercised. Testing the easy part feels like progress and produces no information. Design the trial around the risk, not around convenience.

Name the one thing you genuinely do not know before starting a trial. Arrange the time so that this specific question gets a real answer.