Custody, in the Michigan Family Court system, is divided into two parts: legal custody and physical custody. Legal custody concerns the ability of one or both parents to make decisions regarding the important events in the child's life (i.e. education, medical, religious). Physical custody describes where the child spends the majority of time.
Barring unusual circumstances, most parents share joint legal custody. Physical custody can be shared by both parents or one parent can have sole physical custody and the other parent will have a parenting time schedule (formally known as "visitation"). The custodial arrangement is determined either by agreement of the parents or if the court decides, then by a standard known as the "best interests of the child".
Custody can be addressed in the following cases: in a divorce action; in a separate custody action; in a paternity case; in a support case; or by filing a post-judgment motion to modify or change custody. Either parent can petition the court at any time to change custody or parenting time so long as there has been some type of change in circumstances or proper cause.