Hi Omar...Just like Robert said it depends on the individual. In addition to BrainEv sessions I listen to deep delta sleep CD's, Dr. Jeffery Thompson, at night, to help with my insomnia issues. So far everything is working fine for me, BrainEv is producing some wonderful and positive results and the CD's I listen to while I sleep help put me in delta sleep. I have not slept or felt this good in over two decades, back when my sleep problems started.
I also have some other BWE CD's from Dr. Thompson and a few from The Unexplainable store. Those CD's I don't listen to daily though, just every once in awhile when I want to experience something different. One of my favorites, in addition to BrainEv, and I don't do it often, is the Gamma BWE also from Dr. Thompson. When my brain is entrained to Gamma waves, it's an unbelievable experience. But too much Gamma can cause anxiety, so I'm careful not to use that one too much.