The primary caretaker of a child is one factor that comes into the picture when you are in the midst of a child custody battle. The court will consider this as one of the factors when it is deciding where the child is going to live.
If you are working on the child custody matters through mediation or a similar method, you might not have to worry about the factors that the court looks at when deciding who is the child's primary caretaker. Instead, you and your ex would work together to come up with a custody agreement.
Cases that do hinge on the primary caretaker point require that several points of the child's life are considered. Which parent helps the child with homework and self care? Which parent puts the child to sleep at night? Which parent ensures the child bathes and eats? Who makes the health care arrangements, education decisions and extracurricular activity plans for the child? Who buys the child clothing and other necessities? Which parent tries to make memories with the child by doing fun activities?
These are some of the points that come into the picture. The judge who is presiding over the case can remove some of these and add in others if the situation requires it. Ultimately, the child's best interest is what the court has to determine in all child custody cases.
There are some other factors that might also come into the decision about which parent gets custody of the child. These include what the child wants if he or she is old enough to express an opinion, the stability of the home environment and the relationship between the child and each parent.
Source: FindLaw, "Preference for the "Primary Caretaker"," accessed June 30, 2017