Souls wishing to obtain critically needed experience in order to become harvestable are incarnated with priority over those who will, without too much probable/possible doubt, need to re-experience this density.
The seniority by vibration can be compared to placing various types of materials into a container and depending on the vibration, the heaviest will eventually be at the bottom and that with lighter energies will be found at the top.
The seniority of vibration is the preferential treatment, which encourages harvestable souls. Each soul aware of time of harvest and the need, on a self-level, to bend mind, body, and spirit towards the learn/teaching of these lessons, is given priority in order that this entity may have the best possible chance of succeeding in this attempt and graduate to next density.
There are many who are behind on the seniority of vibration list who would be upcoming next as far as the window of graduation stays open. This is also why many entities have always stated the importance of this current incarnation for many entities.
An “old soul” is term applied to those who seem to create for themselves an experience of simplicity and contentment and no recognition is given to them as accomplishing anything in particular. However, from a larger perspective their contributions are a major balancing factor.
Old souls also include the so-called star seeds.
9.1. Star Seeds
Star Seeds are 3rd density souls who incarnate on the planet earth from other planetary systems. These star seeds are those souls with seniority of vibration who incarnated on planet earth mostly to access the graduation window into the fourth density consciousness.
In comparison, the wanderers are higher density souls who incarnate on the planet earth from other planetary systems but their main purpose is to assist other beings during this ascension process. Wanderers sacrifice their polarisation to be of service to the one infinite creator and incarnate by going through the veil of forgetfulness in order to increase the planetary vibration of earth by sharing love and light energies.