What are the "best interests" factors used by a judge to determine whether or not a child should be removed from the custody of the custodial parent and placed with the access parent?

At paragraph 49 to 50 of Gordon v. Goertz, McLachlin J. stated: 49 ...5. Each case turns on its own unique circumstances. The only issue is the best interest of the child in the particular circumstances of the case. 6. The focus is on the best interests of the child, not the interests and rights of the parents. 7. More particularly the judge should consider, inter alia: (a) the existing custody arrangement and relationship between the child and the custodial parent; (b) the existing access arrangement and the relationship between the child and the access parent; (c) the desirability of maximizing contact between the child and both parents; (d) the views of the child; (e) the custodial parent’s reason for moving, only in the exceptional case where it is relevant to that parent’s ability to meet the needs of the child; (f) disruption to the child of a change in custody; (g) disruption to the child consequent on removal from family, schools, and the community he or she has come to know. 50 In the end, the importance of the child remaining with the parent to whose custody it has become accustomed in the new location must be weighed against the continuance of full contact with the child’s access parent, its extended family and its community. The ultimate question in every case is this: what is in the best interests of the child in all the circumstances, old as well as new? Findings on “best interests” factors