Some strictly practice Brahmacharya (celibacy) and others may require complete renunciation of worldly life.
Shastra (Sanskrit and Hindi: शास्त्र) means treatise, scriptures or the school of thoughts based on those.
There has been a long monastic tradition of obtaining "Shashtra Vidhya" (knowledge of sashtras) in various Sampradaya schools of thoughts in Hinduism, where disciples could learn one or more of the following in a monastic setting: Hindu scriptures, Yoga Sashtra, Vastu shastra (architecture), Vaimānika Shāstra (ancient aerospace technology), Jyotiḥśāstra (astrology), Nadi sashtra (fortune telling), Rasa shastra (medicine), Shilpa Shastras (arts and craft), Natya Shastra (dance, drama and performing arts), Tantra, Para Vidya (Higher scholar), Madhu-vidya (knolwedge of bliss), and so on.
Among these, today, three are considered major akhara (Juna, Niranjani and Mahanirvani) and three minor akhara (Avahan affiliated with Juna, Ananda affiliated with Niranjani and Atal affiliated with Mahanirvani).
The 7th, small Brahmachari (celibate) akhara named Agni is also affiliated with Juna Akhara.
Though not all akharas follow this structure, mainly due to the insufficient size.