Ashram refers to a stage or phase in the life of a Hindu. There are four accepted ashrams. These are: Brahmacharya, for studying; Grihastha as a married man and householder; Vaanaprastha, for performing penance in a forest; and Sanyasa, for renouncing worldly attachments.
According to the Manusmriti, the span of a human life is 100 years. Every Hindu man was to spend a part of his life in each of the four ashrams to fulfill his obligations: to the sages by studying, to his ancestors by raising male progeny, to the gods by performing penance and sacrifices, and for the salvation of his soul (see Moksha) by renouncing the world. This was assuming, of course that he lived his full life span.
Vaanaprastha stage indicates the beginning of old age. Living away from society in the forest, he should live simply, perform sacrifices, and prepare to renounce all worldly associations. A man may take his wife to live with him in the Vaanaprastha ashram, in which he stays until he is 70 years of age. He then returns from the forest and a purification ceremony initiates him into the Sanyasa ashram.
In this last phase, a man renounces wealth and worldly pleasures, and is called a sanyasi. He is completely detached from the rest of the world giving up even those family ties allowed in Vaanaprastha.
This division of a man's life into different phases followed a practical rationale. In the earlier part of his life, a man is more open to ideas and instruction, since his thoughts have not yet taken a definite shape. His energies and capabilities are unused and can be best channeled into learning, as in the Brahmacharya ashram. The next 25 years are spent in the Grihastha ashram, where a man uses the knowledge he gained as a student to live a complete life and enjoys worldly pleasures without a sense of guilt. After 50 years, the physical senses become weaker but inner strength increases. Satiated with the world, a man turns to the spiritual aspects of life in the Vaanaprastha ashram. He goes on pilgrimages and slowly detaches himself from worldly affairs. After a point, he realizes that all attachments, even to his wife, are no longer necessary, and he has the ability to completely isolate himself mentally from the world. This marks the Sanyasa ashram, which is the last stage in a man's life