This canon means that the taxpayer should know how much tax he has to pay, the time by when it must be paid and the manner in which the tax must be paid Thus, for example, the amount to be paid in tax should not be an arbitrary or based on discreation of the tax administration or official. This canon is very relevant to date as the protection of taxpayers from unnecessary harassment by the tax authority is a required standard of a good tax system, and also the practise of integrity and zero tolerance for corruption in the tax administration is highly regarded as a vehicle for the efficiency and effectiveness of a tax agency as reflected in many literature on good governance.
This canon means that taxes must be collected in a form and time convenient to the taxpayer. This canon takes into consideration the interest of the tax payer from the view of payment of tax that the method and timing of the tax should suit the taxpayer. An example is the collection of income tax as income is recieved by the taxpayer instaed of when is likely that the income is spent all that income. This canon is important in protectign the tax administration from the posibility of facing problems of tax evasion and avoidance which coul dhave been avoided