I don't have first-hand experience with this. But I have studied the writings of many Indian yoga meditation masters in the lineage of Kriya Yoga. I also have currently been studying under an Indian Kriya Yoga master for the past two years. All the teachings that I have encountered put it this way: Because of your attachments to the physical body, mainly due to sensory attachments and karma from our past actions, we reincarnate into a physical body over and over until we work out all our past and present karma. Once we are free from karma and we realize our eternal nature as spirit, then there is no need to incarnate into a physical body any longer. I cannot verify this from my own personal experience but what I can say for sure is that we are definitely spirit in nature and the physical body is just a temporary housing for us.