Sree Sree Guru Gaurangau Jayatah!
Previously in ancient times, Varnashram Dharma was prescribed according to quality and action four Vranas and four Ashrams were introduced. Four Vranas Brahmin, Kshatriya, Vaishya and Sudra. Four Ashrams Brahmachari, Grihastha, Vanaprastha and Sannyasa.
Incompetent persons, finding difficulty after marriage to lead household life and to maintain family members, give up family life. By that they commit sin. Acceptance of Sannyasa for them is prohibited. There may be some exceptional cases by providence, some fortunate persons may come in contact with bona fide sadhus and get chance of getting the temperament of worshipping God and leading restricted lives.
In Srimad Bhagavat, third canto, Kapil Bhagavan in His instruction to mother Devahuti said about the original and concomitant qualities of a bona fide pure devotee sadhu. He mentioned in His instruction, one of the original qualifications of sadhu should be `Mat-krte tyakta-karmanas tyakta-svajana-bandhavah' abandoning of Varnashram dharma and relinquishing of bodily relations and friends are allowed if it is for the propitiation of Supreme Lord. In case there is any other ulterior motive, to fulfil material desires, then abandoning of Varnashram duties and relations will be considered as sinful act.
--- His Divine Grace Srila Bhakti Ballabh Tirtha Goswami Maharaj