A 42-year-old woman with bipolar I disorder has been stabilized for three months following a severe manic episode that required hospitalization. During the episode, she was started on lithium and an atypical antipsychotic. She is now euthymic, functioning well at work, and has a YMRS score of 3 and a PHQ-9 score of 4. She has had three manic episodes and two depressive episodes over the past seven years. Her lithium level is 0.8 mEq/L, renal function and thyroid function are within normal limits, and she reports no significant side effects from her current regimen. She asks the PMHNP when she can stop her medications. Which of the following best describes the appropriate maintenance treatment planning approach?