I am the leader of the Asgard Civilization. I am also the military commander of the Universal Elite Troops of Spiritual Warriors. And my passions are general science, writing and listening to music.
Wife and husband who make a single Living child are granted each reincarnation. If they make two, one of the parents must give up reincarnation. If they make three both parents lose reincarnation.
Exceptional temporary situation: due to the large number of souls waiting for reincarnation the rule of 1 child is set to two children.
God is the only one who decides if a baby will have a new soul or an old soul will reincarnate instead.
Where do people reincarnate and when?
No Soul, positive or negative, can leave the planet. Except for Paradise Creators.
The fallen angels (dark Souls) always get destroyed. The rest of the negative people (psychopaths) sell their Souls to the devil so they lose reincarnation too because they have no Souls anymore.
So what remains are positive people. The more positive they are during their lives the less time they spend between reincarnations because they have fewer mistakes to reflect on and lessons to learn and integrate into their Souls.
For positive people it is best practice to leave a notebook behind with information they want to remember in their next life. God will make sure they either receive the physical notebook at 7 years old or they are told the information in the notebook by God Itself. Another best practice is to ask an alive person to deliver the notebook (or the information inside it) if the person will reincarnate before. Such people are called Reincarnation Guides.