Who doesn't want to retire early, and quit work early, to go home - to find moksha in Sannyasa. But though you might live in the Vana, the Forest, and dwell as a Vanaprastha, the desire, the Vana, must be sacrificed to achieve non-desire (ni-vana): first, accomplish Grihastha
Sannyasa requires the ni-vana sacrifice of Vana-prastha, and this sacrifice requires an altar, which is constructed through the study of architecture, home-making, in Grihastha. Such construction cannot be undertaken without study, the seeking of Brahma, the spirit of Agni-Svaha.
What is placed upon the fire must first be held in hand, and in heart. One must first adopt the worship of the Gods before giving it up, or else it is a practice of atheism, rather than Vedasamnyasa, and Sattrayana. One must make one's self worthy of the self-sacrifice.