A 72-year-old woman from Mumbai is found to have an elevated WBC count of 18,000/μL on routine blood work. Peripheral blood smear shows predominantly small lymphocytes with smudge cells. Flow cytometry confirms CD5+, CD19+, CD23+ B-cell population. Bone marrow biopsy shows 35% lymphocytes. A diagnosis of chronic lymphocytic leukemia (CLL) Rai stage I is made. The patient is asymptomatic with normal renal and hepatic function. What is the most appropriate next step in management?