Firm faith in Sadhu (saints), Guru (spiritual mentor) and Shastras (scriptures) is called Shraddha.
There are three types of Shraddha: Sadharan Shraddha, Vishesh Shraddha and Atyantiki Shraddha.
1. Sadharan Shraddha: A sadhak with Sadharan Shraddha visits Sadhus and his Guru occasionally and tries to serve them according to his convenience. He listens to Their lectures and tries to perform devotional services a little. He gets entangled in worldly matters most of the time, but sometimes, remembers that he must associate with enlightened Sadhus to develop Bhakti for Krishna. Thus, he visits Them for a few days but again gets entangled in Maya when he comes back.
2. Vishesh Shraddha: A sadhak with Vishesh Shraddha tries to remain in association with Sadhus/Guru as much as possible and pleases Them through Their service. He tries to follow Their instructions with determination in his life.
Such sadhaks must keep in mind that if they start finding faults in Sadhus/Guru, their Shraddha will get destroyed and they will end up committing Guru/Vaishnav Aparadhas instead of deepening their faith in Them.
3. Atyantiki Shraddha: A sadhak with Atyantiki Shraddha considers Sadhus/Guru indifferent from Krishna and follows Their instructions with complete devotion. He tries to please Them in every way possible and even surrenders his own will/intellect at Their lotus feet.
If, occasionally, he feels there is a conflict between his will/intellect/attitude and what They instructed him to do, he becomes worried and prays to his Guru, “O Gurudev, I have developed my independent will and I am unable to surrender completely myself at Your lotus feet. Please bestow Your mercy upon me so that I can do so.” The sadhak develops such love for his Guru that he is unable to stay calm without seeing his Guru or being near Him.
Such great Shraddha for Guru is rare in this world and it cannot be developed artificially. This kind of Shraddha is possible only through the Samskar of devotion to Guru through many previous lives.