Horizontal equity is difficult to achieve because: equity needs to be measured over 5 years, not 1 it doesn't apply to progressive tax systems taxpayers with several children are better off it is hard to determine the most appropriate tax unit To be a fringe benefit, there must be a relevant benefit provided by an employer , an associate or other relevant person: O to a third party associate of the employee in their capacity as associate; O to an employee or associate solely in relation to that benefit as such; O to an employee or associate in respect of the employee's employment; O to an employee or associate in relation to their capacity as an employee