There is no definitive answer to this question since everyone experiences binaural beats differently and for varying lengths of time. In general, however, most people report feeling the effects of binaural beats for at least a few minutes after beginning to listen. Additionally, some people may find that they can continue to experience the benefits of binaural beats for several hours or even days after listening. Ultimately, it is up to each individual to experiment with different times and frequencies to see what works best for them.