Is Sandhya-Vandana not Hari-Bhajana? Do the divisions of Hari-Bhajana have some secondary results? Is There any difference between Sandhya-Vandana and the practices that constitute Vaidhi-bhakti (Bhakti that is performed by rule, law, religious injunction or regulation), such as Sandhya-vandana?
Sandhya-vandana is the chanting of Vedic mantras such as brahma-gayatri at dawn, noon and sunset.
Sravana (hearing the transcendental descriptions of Bhagavan’s names, forms, qualities, pastimes, and associates from the mouths of advanced devotees)
Kirtana (congregational singing of Krishna’s holy names and glories, sometimes accompanied by music). This may also refer to loud individual chanting of the holy name, as well as oral descriptions of Bhagavan names, forms, qualities, associates, and pastimes).
The sandhya-vandana that is included in karma-kanda (a division of the Vedas, which relates to the performance of ceremonial acts and sacrificial rites directed toward material benefits or liberation), is significantly different from vaidhi-bhakti. Sandhya-vandana and other such activities are performed in the karma-kanda system in order to obtain liberation.
However, activities of hari-bhajana, such as sravana and kirtana, have no ulterior motive. The scriptures describe the results of hearing, chanting, and the other limbs of vaidhi-bhakti, but this is just to interest people who would otherwise not be inclined to perform those activities. The worship of Sri Hari has no fruit other than the service of Sri Hari. The principal fruit of the practice of vaidhi-bhakti is to bring about the awakening of prema in hari-bhajana.
However, the results depend on the different types of practitioner (sadhaka).
The Vaisnavas perform sadhana-bhakti for the sole purpose of
coming to the perfectional stage of devotion known as siddha-bhakti, (one who is always fully immersed in activities related to Sri Krishna, who is completely unacquainted with impediments or material distress, and who incessantly tastes the bliss of prema is called a siddha-bhakta).
When non-Vaisnavas perform the very same divisions of bhakti, they have two principal motives: the desire for material enjoyment (bhoga), and the desire for liberation (moksa).
Externally, there is no apparent difference between the sadhana practices of the Vaisnavas, and those of non-Vaisnavas, but there is a fundamental difference in nistha, (firm faith; steadiness in one’s devotional practices; this is the fourth stage in the development of the creeper of bhakti).
When one worships Krishna through the path of karma, (good works and deeds), the mind is purified, and one may obtain material fruits, freedom from disease, or liberation. However, the same worship of Krishna through the path of bhakti produces only prema for Krishna-nama. When karmis, those who follow the path of karma, observe Ekadasi, it eradicates their sins; whereas when bhaktas observe Ekadasi, it enhances their hari-bhakti. Just see what a world of difference there is!
The subtle difference between sadhana performed as an aspect of karma, and sadhana performed as an aspect of bhakti, may be known only by the mercy of Bhagavan. The bhaktas obtain the primary result, whereas the karmis are caught up in the secondary results, which may be broadly divided into two categories, namely, bhukti, (material sense enjoyment) and mukti (liberation).
FOOT & END NOTES:
 Ekadasi fasting from grains and legumes on the eleventh day of the waxing or waning moon. Suddha Ekadasi means that the whole eleventh day of the moon elapses during the period between one sunrise and the next. Viddha Ekadasi means that the eleventh day of the moon begins on one solar day (sunrise to sunrise) and finishes on the next solar day, that is after sunrise on the next day. In case of viddha Ekadasi, the observances are made on the Dvadasi i.e. the twelfth day of the moon.