Music pieces repeat about 3 to 4 times a year. The music itself doesn’t provide any benefit other than making it easier to listen to compared to just "raw" frequencies. It is the frequencies embedded inside the music which are important.
We alternate the stimulus (waveform) and intensity (amplitude) of the frequencies for every session. This is necessary for the program to remain effective. So even though you will hear music pieces repeat, the stimulus always changes.
With that said, we continuously create new music for the program so that users have the best and most enjoyable experience possible.