Child support is a monthly sum, paid by the parent who has the child for the least amount of time, the ''payor'', to the parent who has the child for the most amount of time, to help cover the day-to-day living expenses of the child. Child support may also be paid when the parents
have equal time with the child but there is a difference between the parents' incomes. The amount of child support that is paid is almost always dealt with by referring to the [[Child Support Guidelines]], which set out the amount of a parent's child support obligation according to the number of children support is being paid for and the payor's income.
A good separation agreement will:
#provide for the recalculation of the parties' shares of the cost of the child's special expenses if either party's income rises or falls.
The Guidelines are an extremely convenient way to calculate a party's child support obligations up to the point where the spouse paying support, the ''payor'', has
access to the child for 39% or less of the time. Once the payor has 40% or more of the child's time, the Guidelines tables become less important, and child support is assessed based on, among other things, each party's income and the amount of expenses related to the child that each party is paying. In the context of separation agreements, this allows for a little more flexibility in determining child support, but makes the annual exchange of financial information even more important.