My belief is a very simplistic one. We are basically energy and, no matter what you do to energy, you cannot kill it, merely change its state. So, when our human incarnation expires, the eternal energy we are, returns home to source, where we develop and learn from our experiences, in preparation for our next incarnation, if we so chose.
We are imprinted with the issues that have affected us in our previous incarnations; issues that were/are there to teach us, to develop us into a balanced harmonious spirit. Part of our development, part of our evolution is to seek the knowledge that we, as an individual, need at this particular stage of our eternal development. Regardless of our current level of development, there is the possibility, for each and anyone of us to carry with us, through various incarnations, the effects of an unjust act. And, because we are a time line of energy that unjust act and/or the effects of it will continue to reply (like a scratched record) at the same time in each and every incarnation from the time of its occurrence until such time as it is identified, acknowledged and left from whence it came.
I apply my very simplistic belief and approach to my Past Life Regression Therapy, bringing fast, efficient and effective relief to a vast array of issues and symptoms.