I sometimes feel my spiritual efforts are fruitless compared to others. Is there an instance in the Satcharitra where a devotee felt this way, and what was Baba's response?

Yes, the Satcharitra addresses this very feeling through the narrator's experience in Chapter 18. The narrator, upon hearing about the spiritual rewards granted to another devotee, Sathe, after just one seven-day reading, felt intense envy and despair. He lamented to himself, "Sathe gets the fruit with little effort, while years of mine have passed... One gets the fruit in seven days, and for another, seven years are fruitless!" As Chapter 18 explains, Sai Baba, who knows all inner thoughts, was aware of this turmoil. His response was not a direct reprimand but a compassionate and subtle lesson. He sent the narrator on an errand that led him to complete a portion of reading he had neglected, thereby teaching him about personal discipline rather than comparing his journey to others.