Every psychotherapy lasts as long as the patient needs it.
In other words, the duration of the therapy is independent of the amount of sessions the insurance will cover. It is misleading to assume that, if the insurance will cover 100 sessions, the therapy will only last that long. Each therapy is different and individuallly biased.
The most profound kind of psychotherapy. It is based on the encounter with the analyst, preferably in a high frequency setting (four to five sessions per week).
The high frequency setting facilitates regression, a psychic process that leads to the evocation of early childhood conflicts, which in turn can be accessed and worked through by the transference/countertransference interactions between analysand and analyst. This is an important step, as these conflicts most regularly are at the root of the psychic disturbance. Thus, a profound elaboration of the personality structure is achieved, allowing for life options that had been foreclosed thus far by neurotic conflicts. These conflicts often show in relationships, anxiety and panic disorders, depression or obsessive compulsion disturbances. Symptomatology can be manifold. Due to the fact that psychoanalysis doesn't work directly on the symptoms but focuses on the personality of the patient, it engulfs a broad spectrum of psychic diseases, as psychic diseases are disturbances of the personality.
Psychoanalysis serves the expansion of the inner psychic world. By this it is aimless and not restricted to a given time frame. All other therapeutic methods - especially the so called legally confounded therapeutic methods ("Richtlinienverfahren") covered by the health insurances - derive their substance from psychoanalysis; psychoanalysis, though, is not covered by health insurances. Nevertheless I find it to be the method of choice in many cases.
You can learn more about psychoanalysis here (in German):
You also may watch a video about the method of psychoanalysis here (in English).
2. Analytic psychotherapy
A psychotherapeutic method derived from psychoanalysis, conducted on a two to three sessions per week basis; the expenses are covered by the health system. Its intention is a limited one compared with psychoanalysis, as the insurances will only grant up to 240 sessions, under specific circumstances up to 300. This method applies when the psychic conflict seems to be confined, and a focus can be formulated that provides a chance to be worked upon sufficiently in the time given. In specific, well defined cases, the health isurance allows for a four sessions per week setting for a limited amount of time, so the patient can make a psychoanalytic experience. Analytic psychotherapy provides a good approach to neurotic conflicts, and it often happens that patients prolong the therapy on their own costs.
3. Tiefenpsychologisch fundierte Psychotherapie
There is no English term for this kind of psychotherapy. You may translate it with "psychotherapy proper". This method is much more limited than the other two described here, both in regard to the time frame (50 to 100 sessions with one session per week) and in its intention. It concentrates on well focused neurotic situations. In the years I worked as a psychoanalyst I have found much less indications for this kind of therapy than for the other methods. This may be due to my point of view on psychic situations as a psychoanalyst; but I assume that psychic constellations are per se much more complicated than is seen on the surface. The closer you look, spaces will open that need to be explored more thoroughly.