I think what you'[re referring to is the Child & Dependent Care Tax Credit. The only way to qualify for that is if the daycare is required in order for both you and your spouse to work. So if you work during the week and the wife is off, and you change roles on Saturday, you don't qualify since both of you are not working at the same time. Therefore, the care is not required in order for the two of you to produce joint income.
