In it's simplest terms, "custody" is the right to make decisions for and on behalf of your child. Having custody does not give a parent the right to dictate the other parent's access schedule, deny the other parent information about the child's educational or medical providers, or re-locate without concern for the "non-custodial" parent. In other words, being granted custody does not make the other party less of a parent. In your normal, daily routine, having sole, joint or shared custody (terms that I will define in subsequent sections), will be of no consequence or concern. It is only when disagreement between the parties arises, that the type of custody becomes important.
If a parent is designated as having "Sole Custody" or simply "Custody", that parent has the right to make decisions for the child, authorize medical treatment, determine school choices, etc., without the authorization of the other parent. It is generally a term of Custody Orders that the custodial parent keep the non-custodial parent (NCP) informed of these decisions. In this situation, if the NCP disagrees with the decision, he or she can petition a Court for relief. For example, if the custodial parent decides to allow his or her 12 year old to be tattooed, the NCP can petition a Court to intervene and Order that the child not be tattooed. However, the tattoo artist is free to perform his work over the NCP's objection, unless the Court intervenes. Now, lets look at this situation if the parties share "Joint Custody."
As previously discussed, custody refers to decision making. When parties share "Joint Custody", they are equally responsible for and have equal rights to make major decisions on behalf of the children. In the tattoo scenario, should the NCP object to the the child receiving a tattoo, the tattoo parlor is bound not to perform its services. Where the child resides, or whether there is access with the NCP does not matter. The same applies to medical treatment. You may notice that I qualified this section by saying it applies to situations that require "major decisions". Most Courts would agree that tattooing a 12 year old qualifies as a major decision. What the child eats for breakfast, which dentist they go to, or in most instances which school they attend (often dictated by residence, to be discussed), are not major decisions. If the parties are unable to agree on what is in the child's best interest, (the gold standard in Family Court), either is free to file a petition
Typically, this arrangement contemplate the parties spending an equal amount of time raising the child, and generally incorporates the basics of Joint Custody as well. An increasingly popular concept that can be incorporated into any custody agreement is the idea of "Sphere's of Influence." This arrangement allows the parties to agree that one of them has the authority to make decisions, as in Sole Custody, but only in limited areas. For example, child resides with Mother who is designated the Custodial Parent, but Father has authority to make all medical decisions. In other words, his "sphere of influence" encompasses medical issues. The spheres can be divided into as many parts as the parties need, such as educational, athletic, extra-curricular, religious, etc.
Often, one party has the designation as the "residential" parent. This designation controls what will be considered the child's school district, as well as be a factor as to who will receive child support. (The issue of child support can be as complex as that of custody. While it is handled separately in Family Court, the issue often looms over the decisions parties make regarding custody.) If a party is designated the residential parent, the other party will often have an access schedule. That access is an important right and should not be hampered or impaired in any way. Many Judges take the position that the number one job of a custodial parent is to foster and encourage a relationship between the children and the NCP.