ĀŚRAMA Asramites (Inmates of an Āśrama) have to pass through four stages. The four stages of Brahmacarya, Gārhasthya, Vānaprastha and Sannyāsa are known as the four Āśramas.
[Viṣṇu Purāṇa, Part III, Chapter 9] describes each of the Āśramas as follows: 1.
Brahmacarya. “After Upanayana a boy should maintain a Brahmacārī's vrata, engage himself in the study of the Vedas, suppress his indriyas (the five senses) and live in the house of the preceptor. Living there with proper observance of śauca, customs and vratas he should serve and attend on the Guru. The study of Vedas should be with proper observance of Vratas and steady attention. A Brahmacārī should worship with concentration, the Sun and Agni at the time of the two sandhyās (dawn and dusk) and after that he should do obeisance to the Guru. When the Guru stands, he should also be standing. When the guru walks, he should walk behind him and when he sits, he should sit in a lower position. The Śiṣya (disciple-pupil) should not do anything against the guru. When the guru himself asks, the Śiṣya should sit in front of him and recite Vedas without attending to anything else. After that, with his permission he may eat food which has been got by begging. The Śiṣya may take his bath in the water only after the Ācārya (guru) has taken his bath in it. Everyday the Camata, darbha, water and flowers which the guru needs, must be brought and supplied (by the Śiṣya). 2.
Gārhasthya. After the study of the Vedas the intelligent śiṣya gives Gurudakṣiṇā (Payment to the preceptor) and with the consent of the Guru, enters into Gṛhasthāśrama. Then he is to marry and by earning money from a suitable occupation, should fulfil all obligations of a Gṛhastha according to his capacity. The Gṛhastha who worships the Pitṛs with Piṇḍadāna (offerings of rice balls), Devas with Yāgas (sacrifices), Ṛṣis with Svādhyāya (self discipline), Prajāpatis with begetting of children, spirits with bali (offering of food etc.) and the whole world with love, attains the holy world by his own virtuous deeds. Gṛhasthāśrama is the only source of support for sannyāsīs and brahmacārīs who beg their food. Therefore feeding them is an act of nobility. Brāhmaṇas travel from country to country to study Vedas, for pilgrimage and for seeing the places. The Gṛhastha is the only refuge and support of those who are homeless, who do not carry their food with them and those who spend the night wherever they reach. If such people come to his house, the Gṛhastha should welcome them with kind and loving words, and give them bed, seat and food. The guest who leaves a house disappointed, is really departing after transferring his own sins to that householder and taking away all the virtuous deeds of the householder. It is not proper for the Gṛhastha to treat a guest with disrespect, to behave rudely or treacherously towards him, to regret what has been given to the guest, or to obstruct or rebuke him. The Gṛhastha who performs the supreme duty of Gṛhasthāśrama in this way properly, is liberated from all secular bonds and reaches the noblest worlds. 3.
Vānaprastha. After having finished all his duties in this way, to his satisfaction, the Gṛhastha, with the commencement of old age, should go to the forest, either after entrusting his wife to his sons or taking her also with him. There, he should use leaves, roots and fruits for his food, grow hair and beard, sleep on the bare ground, lead the life of a tāpasa and receive and honour all classes of guests. His clothes, sheets and blankets should be of deer-skin and darbha grass. The rule is that he should bathe three times a day. Worship of gods, performing homas, hospitality to all guests, mendicancy -all these are the laudable features of Vānaprastha. Any oil that is available in the forest is to be used for his oil bath. Enduring heat and cold, performing tapas, are also his duties. The Muni who observes this rule in Vānaprastha with due austerity, burns up all his evils as with fire and attains the eternal worlds. 4.
Sannyāsa. The fourth Āśrama is that of the Sannyāsī. Before entering upon the fourth Āśrama one has to renounce the love of travel, wealth and wife and also give up all spirit of rivalry. One who embraces sannyāsa should abandon completely the efforts for the three Puruṣārthas of Dharma, Artha and Kāma, treat friends and foes alike and continue to love all living beings. Not even a single creature should be offended by thought, word or deed. Conquering all passions, the Sannyāsī should renounce all bonds and attachments. He should not stay in a village more than one night and in a town more than five nights. Even that should be in such a way that no one feels any love or hatred towards him. For sustaining life, he should go about begging food from the houses of the people of the three castes--Brahmins, Kṣatriyas and Vaiśyas. It should be after all people have taken their food and put out the cooking fire. The Sannyāsī should cast away all vices like Kāma, Krodha, Garva, Lobha, and Moha and should not have any thought of self in anything. The Muni who goes about giving shelter to all creatures will not have to fear any creature. The Brāhmaṇa who follows the Sannyāsāśrama as described above with a pure heart and without difficulty will shine like fire without fuel and attain Brahmaloka in peace.