In Bartleby the Scrivener, why does the narrator spend the first few pages talking about his personal concerns and his change of economic fortune as well as his age?

The early paragraphs frame the character for us. The narrator's initial self-characterization is important to the story. He is a "safe" man, one who takes few risks and tries above all to conform. The most pragmatic concerns of financial security and ease of life are his priorities. He has made himself perfectly at home in the modern economy: he works as a lawyer dealing with rich men's legal documents. He is therefore an opposite or complement to Bartleby in many ways. He is also ill suited to be entrusted with the salvation of another.