Withholding thresholds in general differ from state to state. Some states impose a day or dollar threshold for employer withholding requirements while the majority of states require withholding immediately upon services being performed in the state. These differences require an employer to understand where employees are performing services in order to adhere to those states' withholding requirements. In addition, the differences require an employee to be aware of how much and where his employer is withholding taxes to determine if such withholding is sufficient to meet his personal income tax payment obligations. Needless to say, this is a difficult process that has long been recognized by employees and employers alike and thus, states and state coalition groups have heard the arguments for a more simplified process for years.