Final answer:
Employers are generally recommended to keep employment and payroll records for a minimum of three to seven years.
Step-by-step explanation:
Under the Worker Adjustment and Retraining Notification (WARN) Act, employers with more than 100 employees are required to provide written notice 60 days before plant closings or large layoffs. However, the question is about how many years licensees must keep employment and payroll records on file, which is not directly addressed by the provided information. The requirement for keeping employment and payroll records on file can vary depending on the specific laws and regulations of each jurisdiction. It is generally recommended that employers keep these records for a minimum of three to seven years to comply with tax and employment laws.