That sounds about right. Every 10 to 15 days. Sometimes more. I do energy work and meditation every day. Two or three times a day if I can. It makes for a more natural exit and a more robust experience. It is still rare for me to induce an OBE at will, but I can do it once or twice every couple of months. I have found that a more natural exit will occur just a couple of days before a full moon. (not sure why) I am 37 year old male and have had thousands of fully conscious exit projections. Most all of them have been natural exits, (didn't have to try).