That all said, we are all different and have our own different limits. So I generally advise that you just be aware of how you are feeling, and if you feel like you are getting a bit fatigued from it, it’s probably time to stop or at least take a break. When listening over long extended periods, I recommend that you keep yourself well-hydrated. Your brain needs a good supply of water to function well, especially if you are studying hard and increasing your brainwave electrical activity.
However, if you are looking to do something more practical, like improve your mental sharpness, overcome attention issues, succeed at work, be more productive, you may want audios that target more of the alpha and beta ranges, and are created to put you in peak performance states of mind. In this case, a program like our Effortless Overachiever Bundle would be much more practical and helpful for you.
But again, when it comes to subjective experience, and mental evolution, I would have to caution you to take what anyone says with a grain of salt. Obviously people want to sell these products. There are some good ones out there and there are some bad ones out there. There are differences in quality, as well as differences in intent with how the audios are to be used.
Both brainwave entrainment and neurofeedback deal with brainwaves, but the similarity stops there. Entrainment pushes your whole brain into a pre-determined state, while neurofeedback teaches you how to move specific parts of your brain on your own. It is the differeence between forcing the brain into a given position, and skills building so you can move it there yourself.