Vodou teaches that the lwa call an individual to become an oungan or manbo, and if the latter refuses then misfortune may befall them. A prospective oungan or manbo must normally rise through the other roles in a Vodou congregation before undergoing an apprenticeship with a pre-existing oungan or manbo lasting several months or years. After this apprenticeship, they undergo an initiation ceremony, the details of which are kept secret from non-initiates. Other oungan and manbo do not undergo any apprenticeship, but claim that they have gained their training directly from the lwa. Their authenticity is often challenged, and they are referred to as "hungan-macoutte", a term bearing some disparaging connotations. Becoming an oungan or manbo is expensive, often requiring the purchase of ritual paraphernalia and land on which to build a temple. To finance this, many save up for a long time.