It is easy to call something an experiment when the real plan is to try it indefinitely. Useful tests are more deliberate.
State the question
Describe what you expect to change and why. Keep it narrow enough that the result could guide a decision.
Set the measure
Choose the signal before looking at the result. Record a baseline if one exists.
Choose an end point
Give the test enough time to observe behaviour, then review it. Continue, change, or stop based on what you found.
The takeaway
The lesson is the output. A test that fails can still be valuable when it changes what you do next.