The session should last as long as the sensations are pleasant. Often you don't feel anything at all - this happens either when the basic charge is very deep, or when you have used the orgone accumulator very often on a regular basis. Then the nervous system has become accustomed to the experience and no longer perceives it as a sensation. If you do not feel anything, you should set a time limit - 15 or 20 minutes. It makes more sense to go to the accumulator often and briefly than once for a long time. Since the body knows the charging process - it is the same function as the desire to be outdoors in nice weather - it then has to get used to increasing the energetic charge from session to session.
If the orgone accumulator has been prescribed by the doctor as a treatment, he will also give precise instructions on how often and for how long the accumulator should be used. In case of severe diseases, i.e. very low vitality, this may well be two times an hour a day.
As soon as perceptions become unpleasant - e.g. hot flushes, head pressure, burning eyes, sweating, etc. - leave the accumulator. If you have overloaded yourself, it is helpful to take a long bath, go for a walk and do without the accumulator for two or three days.
The organism should actually be able to determine the length and frequency of the sessions itself. As with food intake, there is a simple biological self-regulation here. We generally know exactly how often and how much we want to eat. Sometimes it happens that we overeat, then we do not feel well for a few hours, but for relatively healthy people this is still harmless. Only frequent or even regular overeating has corresponding negative health consequences. These self-regulating mechanisms apply analogously to the orgone charge.
There is no point in being too anxious about this. For a healthy person a single strong overcharge is not harmful, in fact I recommend to get a strong overcharge at least once by putting 5 to 10 minutes each hour into the accumulator from morning to evening on a nice dry day with deep blue sky and fleecy clouds. Then you will most likely experience a severe overcharge. The meaning of this is to know this experience sensually. Whoever has experienced something like this will never doubt the energetic charge again and will know what is an appropriate energetic charge and what is an overcharge. As long as one has not experienced it, it is a mere idea without sensory experience, and many people tend to mystify the things they know about but do not know them and to interpret all kinds of things into it.