While I agree that most do try to keep the therapy relationship as long as possible, there is a natural sense of when to terminate when it's no longer needed. If you have to question yourself, you probably aren't there yet.

The fear that T will abandon you (the patient) is natural, and with that comes the desire to keep the T for as long as possible. There's nothing wrong with that (in spite of what the HMOs say.) Having assurance that the T will be there for the long haul is a good foundation for not feeling rushed. Often it's the slowing down of therapy that allows you to accomplish more, and often more quickly.

If your dx usually necessitates long term therapy, or your natural ways of healing do, it's best to find a T that will be there with you, to the end if possible. Ask!