This is not easy to grasp but Seth speaks volumes here. Nothing is ever lost. All memory is maintained, regardless.
Seth: “A death is but one night to the soul. The vaster entity of which you are a part follows your progress as easily as you follow you own through the days. As a rule most of you wake up in the same bed in the same house or town, but certainly you wake up as the same person in the same century.
In those terms the entity wakes up as a different person each day, in a different century, each life seeming like a day in its level of experience. It carries the memory and simultaneous experience of each of those selves.”
“The Nature of Personal Reality” by Jane Roberts, Session 655