Decision to start medication at that time could be because of need to correct depressive features presenting as insomnia. One needs to continue treatment for minimum 6-9 months as it's the usual course of maintainance management. If you are symptomatically better and following healthy lifestyle you need not start the medications now. However, considering the nature of illness which has chances of relapse in future you need to be watchful if signs of relapse like sleeplessness, low mood, irritability, difficulty concentrating etc. And consult a psychiatrist then.