In other religions, they are get to know what they can do and don't during prayer meetings.In Islam most of them perform their Nithya karma without any fail...even if they have doubts they can ask ustad in palli. In Hinduism except Brahmins (minor in numbers), others even don't know their Nithya karma. Even no one is available to guide. It is upto our interest, to read scripture and learn nithyakarma. Is that not strictly mentioned in our scriptures to follow Nithya karma?
Vedic Nitya karma is for all the Dwijas, they certainly include 3 varnas. In my other answer here I have also discussed that even Women are allowed for Vedic nitya karma.
Vedic life involves following the tenets of Vedas which mainly involves fire worship and other Vedic karmas. Further, Samskaras are also part of Vedic life. Along with that one has to contemplate on the supreme lord.
Our Vedic rishis and maharshis have set an example for us towards leading a life according to Vedic injunctions.
Before marriage the bachelor learns the Vedas and after marriage continues to follow the Vedic life along with the spouse which involves agni upasana (agni hotra) and other nitya karmas like sandhya vandana, bali vishvedeva, tarpanam etc.
AykAshramyam tvacAryA: pratyakshavidhAnAt gArhasthasya | (Apasthamba Sutram)
Meaning - There is only one Ashrama and that is Grahastha dharma. Thus, the only Ashrama advocated by the vedAs is the eternal gArhastyAshramam and none other. This is the reason why all our seers (cause for our gotrAs) like atri , vasishta ,agastya , bharadvAja ,etc led a lifestyle of jaDa, maravuri, living with consort in the forest, doing penance, performing daily rituals (nitya karmA) , upAsana (worship) of agni , yagnyA and chanting of vedAs until their last breath.
It should be understood that there is no virtue that is superior to "Daampatya-dharma’, the path of married life. Every one should follow this advice of wisdom-Incarnate throughout their life time as wedlock is the way to salvation. One can never experience the fruit of creation without Wedlock. Male and Female species in creation are complementary to each other. One can become whole and complete only after Wedlock. Without Wedlock neither man nor woman can attain fulfillment- they will remain incomplete.
The cause of this universe and the basis for all existence is the penance of Brahman. The result of unswerving penance is knowledge (vidya), gnyAnam , satyam (truth) , sukham (Happiness). This world, created by, and resulting from unswerving penance, has these aspects of form: vidyArUpam , gnyAnarUpam , satyarUpam , sukharUpam . The same is bestowed upon us by the vedAs. Vedas have provided a platform for every soul (being in their respective states) to experience this 'Brahman'. ( the ultimate power)
The main objective of all the Vedas is ‘garhastyashrama’ i.e, family life (dampatya). ‘Brahmacharyam’ is instrumental and the preliminary practice for ‘garhastyashram’. Brahmacharyam is the life of Veda adyayanam, enjoying all sorts of happiness, well being, etc i.e. Shastric veda adyayanam is brahmacharyam. Brahmacharyam is also known as ‘garhasyta sadhanam’ as it is preliminary and part of the garhastyashramam referred to in the Vedas. Brahmacharyam which is the life of Veda adyayanam and Gayathri upasana is applicable for all, irrespective of their sex and creed. The regulated proper method of mastering Vedas etc., helps one lead Dhampathya life successfully. This is applicable to woman also. Women are entitled to all ceremonies like Upanayanam, etc.
Mastering the Vedas as ordained is itself a Tapas (Penance). It must be noted that Karma (or action) and Jnana (or knowledge) are not two separate entities. Therefore there is no separate path for Jnanamarga. There is only one path, and that is Vedamarga, the path of the Vedas. Its culmination is in Dhampathya life. The Maharshi couple led the Dhampathya life throughout their lives. Remaining in that Dhampathya, one should desire good progeny, beget ideal children and bring them up with great care. They are the true wealth for ‘the here’ and ‘the hereafter.’ Immortals are fortunate enough to hear the lisping of their children. In a sense, one can attain immortality, if, being of good character, one is born as his/her own progeny. The Vedas state this explicitly.
When a man and a woman of pure conduct, bound by mutual love, consummate their marriage, all elements like form, etc., get totally absorbed in the fire of their union. This absorption creates an intoxicating light radiating from them. When this intoxicating light is also absorbed, Ananda, or Bliss arises and shines forth. The light is absorbed in itself, and Ananda shines. From that, issues forth a child, the sum total of all elements. The Maharishis advised- Always live in the state of Vedic Dampatya.
The Mahashakthi who created the whole universe, laid down the vedic path so that all mankind could live happily enjoying all comforts- temporal and spiritual. The Vedic path is nothing but the life lived by the Maharshis: the eternal dhampathya life enjoined by the Vedas.
“uthishtatha maaswapta agni michadhvam bharataaha” (YV)
This means “ O Bharathiyas! Awake and yearn for fire”, Bha in Sanskrit means light. One who worships light is a Bharateeya. That India is called Bharat clearly conveys that all Indians were following the Vedas and leading a life as prescribed by the Vedas. It extols all to worship fire which is the primordial energy behind all creation
Vedic path refers to the three stages of a person:
The initial stage, which is Brahmacharya: the study and learning of Vedas and Gayathri Upasana, and worship of Agni through oblations twice a day.
The next stage is the Grihastashrama (getting into marital life) and offering oblations to Agni by performing Agni upasana , Yagas , etc. along with the life partner which are meant for the evolution of one’s self in the spiritual realm.
The final stage is offering one’s body after death to the Agni that was worshipped.
It should be understood that vanaprastha is the continuation of grahastha stage after discharging the duties and retiring along with the wife and continuing agni upasana, penance, and nitya karmas.
To lead a life as prescribed by the Vedas, here is the system to be followed by one and all:
Initiation into Gayathri Upasana Study of the Vedas or understanding the messages given in them. Agni upasana as part of Gayathri Upasana and vedic study (BRAHMACHARYA). Getting into married life and continuing Agni Worship as a couple – Grahastha Dharma. Offering one’s body in the fire worshipped by the couple (The concept behind the ritual followed for cremation in the present day) Source