Conventional labor supply studies assume constant eligibility monitoring of income-tested program participants, but this is not true for most programs. For example, states can allow children to enroll in Medicaid/CHIP for 12 months regardless of family income changes. A long recertification period reduces monitoring costs but is predicted to induce program participation by temporary income adjustments. However, I find little evidence of strategic behavior from the 2001 and 2004 Survey of Income and Program Participation. Given the lack of dynamic responses, I propose a framework to compute the optimal recertification period and find 12 months to be its lower bound.