Is it necessary to get Sai Baba's permission before leaving Shirdi, and what is the role of Udi in this process?

Yes, the texts emphasize the importance of receiving Sai Baba's permission before departing from Shirdi. As described in Chapter 35, transgressing his command and leaving by one's own will is considered an invitation to obstacles, remorse, and humiliation on the journey. The process of receiving permission is deeply connected to Udi. When a devotee goes to Baba to ask for permission to leave, the blessing, along with the gift of Udi, is the actual signal of permission. The text states that unless Sai's heart is pleased, no one gets this permission along with the Udi Prasad, highlighting that departure is as much under his divine will as arrival.