Hinduism recognizes four main stages of life. Like the goals of life, these can be divided into three plus one, with the three deriving from the "life is good" strand of Hinduism, and the one deriving from the "life is bad" strand. The first three are the student, the householder, and the retired person, while the fourth is the ascetic (also known as a sannyasin or a sadhu).
The three stages of life that come from the life-affirming, Vedic side of Hinduism, were intially designed with the caste system in mind (of course). In particular, they were set up to apply to members of the three Twice-Born varnas: the Brahmin, the Kshatriya and the Vaishya. Other castes and jatis have adopted them in different ways, transforming them to meet their needs.
The first stage is that of the student, during which a boy traditionally is expected to go to live and study with a teacher (a guru) for several years. Today only a few Brahmin families follow this tradition to the full extent. A boy enters into student-hood at adolescence (ages 8-12), and spends most of his maturing years studying. For Brahmins, this would mean studying and memorizing large portions of the Vedas and accompanying texts, along with training in the various rituals. Members of all castes learn how to set up and maintain their own household worship, centered on the holy fire of Agni.
For the Twice-Born castes, the ritual (samskara) of becoming a student contains great significance, for it is the means by which a person becomes reborn. This ceremony--often called the thread ceremony because of the red thread which the initiate wears over his left shoulder--symbolizes the entrance of the boy into Hinduism. Originally, it was at this point that the initiate was first permitted to hear the words of the sacred Vedas and learned his first mantra. Once initiated, the boy became, like other Twice-Born males, responsible for maintaining the balance of the cosmos.
After student-hood, the next stage of life is that of householder, usually entered into through an elaborate, many-day marriage ceremony. It is during this stage that a man has children (with his wife), forms a family, establishes himself in a career or job, and strives to be an active member of his community. He will establish his own household, with its own worship. Indeed, with his wife, the householder is now responsible for ensuring that the rituals of domestic life are carried out at their proper times and in the proper manner. This stage is important because it carries the responsibilities of looking after and supporting people at all other stages, both male and female.
The third stage of life is that of retirement. When a man reaches old age and his son has a family and is ready to take over the leadership of the household, he and his wife will retire. On the one hand, their household responsibilities--both religious and secular--diminish significantly. On the other hand, they become free to contemplate the meaning of their coming death and rebirth. They may choose to withdraw into a secluded area--perhaps become a "hermit"-- or they may involve themselves in more active worship (bakti) of Hinduism's pantheon of gods and goddesses.
Each of these three stages is preceded by a samskara, a ritual that brings a person from the previous stage of life into the new one. While these are the most important stages of life, brought on by the most elaborate samskaras, there are many other samskaras performed during one's life. Traditionally, a person may undergo anywhere from 10 to 18, even up to 40, samskaras during their lifetime. The majority of these will be performed before a baby is even six months old, with many of them done before birth. These are believed to help a person leave their previous life behind and to enter successfully into their new one. Each samskara advances a person further along the path of life, initiating them into a new aspect or stage.
It is clear that the three main stages of life are designed for males and do not include women. Traditional Hinduism, like many religions, places women in a dependent role. In the traditional view, women always need the protection of a responsible male, whether father, husband or adult son. This does not mean that women have no religious life. On the contrary, women are actively involved in worship, both in support of their family and on their own. On the one hand, a married woman is responsible for carrying out many of the domestic rites along with her husband. Many rituals cannot be performed with her involvement or in some instances leadership. On the other hand, women are often active practioners of forms of bakhti yoga, that is, the worship of the gods and goddesses. In the modern period, this subordination has begun to change and women have gained more active roles in public life. Indira Ghandi, for instance, was a Prime Minister of India for many years (women have yet to gain a corresponding position in the United States).
The fourth stage of life breaks the progression of the other three; it is that of the ascetic, who in Hinduism are called the sadhu or the sannyasin. This is a rejection of life and all that it means in exchange for a search to attain moksha, that is, release from the cycle of samsara. A person may enter into this stage of life at any time.
The rejection of life, especially as defined by the life-affirming strand of Hinduism, is complete. It requires rejection of the household duties and responsibilities of all stages of life. It also requires the rejection of the religious beliefs. Indeed, the ceremony making one a sannyasin includes the burning of copies of the Vedas, a symbolic rejection even of one's role in maintaining the cosmos, and of one's red thread, the symbol of their status as Twice-Born. It is such a powerful rejection that a person even loses their caste affiliation; even a shudra can become a sannyasin and lose their low-caste identity.
The sannyasins become wandering hermits, living life without any shelter or possessions. They eat when they can acquire food, but never enter into any work to acquire it; it must be given or found. They become holy men, seeking spiritual enlightenment and power, striving to achieve the true wisdom of the cosmos. Some may become kind and give blessings to those around them, while others may become wrathful and powerful and wield magic against those who cross them.