What was the specific vow Cholkar made to Sai Baba and what personal sacrifice did he undertake while waiting to fulfill it?

Cholkar's vow was to visit Shirdi and have Sai Baba's darshan. However, as a worldly man, he found it difficult to manage the expenses for the trip. As a personal penance during the long delay, Cholkar made a specific sacrifice. As described in Chapter 15, he vowed to avoid sugar as if it were an inedible substance. This commitment was so strong that he even drank his tea without any sugar until the day he could finally fulfill his pilgrimage to Shirdi and see Baba.