Can you say why the session begins and when it ends?

One purpose avoids a moving target

What purposes does the handbook describe?

A controlled profit attempt, points under strict caps, or a single predefined shot. The important rule is to choose one before play. Do not begin with one aim and collect replacement explanations when the result disappoints. A purpose is useful because it tells you what the attempt is for and when that reason no longer applies.

Can I pursue points while trying to make a profit?

Points may arise during a session, but the handbook does not let you use several missions to keep it open indefinitely. Choose the governing purpose. If a profit attempt fails at its boundary, it does not become a points session just because the machine recorded action. If a capped points attempt reaches its boundary before the target, the boundary still ends the attempt.

Define success and failure before excitement

What does a clearly defined ending look like?

In an illustrative example, a player chooses one bounded attempt and decides beforehand what result would complete it and what exposure would end it unsuccessfully. We do not need to invent a promising machine to explain the rule. The attempt ends when the chosen condition arrives, or earlier if the person can no longer decide calmly. A purpose cannot be so vague that every result permits another spin.

What if the next machine seems better?

It has to fit the same original boundaries. Changing cabinets does not erase what you have spent or create a new reason to recover it. Scott’s memoir describes limited tests on candidates, but the larger allowance still governs the whole sequence. The scenery can change; the accounting and ending cannot quietly reset with it.

Let completion remain complete

A session that ends according to plan does not need to justify itself to the room. The handbook makes leaving an action under your control. You may feel that something remains possible, but possibility is not an obligation. The full chapter explains why a clear purpose is the foundation underneath the individual game references.