Employers must allow workers to carry unused sick time over to the next year — which is not part of many employers' current policies — but how that is portioned out depends on whether the employer and worker are covered by the Family and Medical Leave Act, a federal law that provides employees with 12 weeks of unpaid leave per year to care for a newborn or attend to a personal or family member's serious illness. The FMLA covers employers with more than 50 employees and workers who have been at the company at least a year.