I found that for me I need a sitter due to the way my brain works. its really helpful for me and keeps my fear and anxiety down if I have a sitter that knows what is going on to be able to help guide me through dark places. each time I have done things alone I have ended up dealing with a lot of fear, but when I had someone around that always helped guide me through the fear to the other side. so it seems to me that its not needed for everyone, it just depends on how your brain works