It should be clear that a certain amount of time needs to elapse before the human being comes back to earth again after death. You might ask, ‘ Yes, when does one come back? ‘ – if one really considers this matter well, the following conclusion arises: the one who has occupied him or herself much with the spiritual world grows into the spirit world easier after death. He or she then has a relatively, because of having been occupied with the spiritual world during the time on earth, longer time between death and a new birth. You may be surprised, that I say: longer. Such a person may stay there for a longer time because he has already learned a lot about the spiritual world. People who engaged themselves with spiritual matters on earth can develop better there, stay longer and come back later. By contrast, those who are only occupied with the material world, come back relatively earlier again.
Source (German): Rudolf Steiner – GA 350 – Rhythmen im Kosmos und im Menschenwesen – Dornach, May 30, 1923 (page 21)
Translated by Nesta Carsten-Krüger