Brahmacharya - The Celibate Student:
This is a period of formal education. It lasts until the age of 25, during which, the young male leaves home to stay with a guru and attain both spiritual and practical knowledge. During this period, he is called a brahmachari, and is prepared for his future profession, as well as for his family, and social and religious life ahead.
Grihastha - The Married Family Man:
This period begins when a man gets married, and undertakes the responsibility for earning a living and supporting his family. At this stage, Hinduism supports the pursuit of wealth as a necessity, and indulgence in Karma. This lasts until around the age of 50.