Endings in therapy are planned rather than incidental. The reasoning is that the way a course finishes influences what remains afterwards, and an unplanned ending forfeits that.
The ending is where responsibility transfers
During therapy, part of the work of noticing patterns and choosing responses is shared with the therapist.
Ending requires that function to move fully to the client, and it is treated as a transfer to be prepared for rather than a switch thrown at the last session.
Approaches differ in method, but most reduce frequency towards the end, so the transfer happens gradually with sessions still available.
Relapse planning is standard in structured therapies
Final sessions in cognitive and behavioural approaches typically involve identifying early warning signs and specifying what will be done if they appear.
The purpose is to distinguish a temporary setback from a return to the original state, since interpreting a bad fortnight as total relapse tends to be self-fulfilling.
Some therapists produce a written summary of what was learned, on the grounds that recall of the work fades and a record does not.
The relationship itself has to be addressed
A therapeutic relationship can be significant, and ending it is a real loss even when the therapy has gone well.
Approaches that emphasise the relationship treat this directly, because how somebody experiences this ending frequently reflects how they experience endings generally.
That makes the final phase a live piece of clinical material rather than an administrative conclusion.
Unplanned endings are common and differ in kind
Many courses end without a planned final phase, through dropout, funding limits, therapist availability or a fixed session cap.
Fixed caps are widespread in publicly funded and insured services, which means the ending point is often set by the system rather than by clinical judgement.
Where that is the case, the ending is usually worth discussing early so that the final sessions can be used deliberately rather than arriving unexpectedly.
Ending is not the same as being finished
Returning to therapy later is common and is not evidence that the earlier work failed, particularly where circumstances have changed substantially.
Many people use therapy episodically across a life rather than as a single course with a definitive conclusion.
Whether that is straightforward depends heavily on local waiting times, funding rules and referral routes, all of which differ by country and change over time.