The vagueness and uncertainty of application of the principles used to determine child custody appeals continue to cause great problems for the legal practitioner who must advise a client aggrieved by a decision at first instance. Child custody is an area where the right of appeal is unrestricted, but appeal court judges have nonetheless shown a marked tendency towards self-restraint in the exercise of their appellate jurisdiction. Two principal reasons are commonly given for this: first, the trial court in a child custody dispute often has a special advantage not possessed by the appeal court, in that it has seen and heard the witnesses; secondly, and more generally, the determination of a child custody dispute involves an exercise of discretion on the part of the trial court, in which the paramount consideration is the welfare of the child. For these reasons, which are considered in detail in the following section, it is perceived to be necessary to allow trial courts a degree of latitude. However, although the necessity for appellate self-restraint is generally accepted, there has been and continues to be wide disagreement as to the form which that self-restraint should take. In addition, there are many reported cases in which an appeal court has acknowledged the need for self-restraint, only to succumb to the temptation to intervene on the facts before it. The result of the absence of a principled justification for intervention is that there is no rational basis upon which parties can assess the strengths of their respective positions.