On the most basic level, the amount of child support should increase and decrease with corresponding (material) changes to the income of the parent who is paying support. Changes in child support may also be triggered by a change in a child's educational status (eg: they begin to attend university) or a change in a child's residential status (they begin sharing their residence with both parents).
Contrary to "prevailing gossip", in Canada, child support does not automatically end when a child turns 18. Such support continues if the child remains "a child of the marriage" or otherwise a dependant, for legitimate reasons.
