Income taxes, the largest proportion of tax revenues, are voluntary and thus must be perceived to be by and large as equitable. Otherwise, tax avoidance and tax evasion may limit tax revenues. Tax avoidance is seeking legal means of reducing taxes. Tax evasion is illegal.
The Internal Revenue Code provides for a variety of methods to delay or avoid taxes in a perfectly legal manner. One example is the use of individual retirement accounts to build a nest egg for retirement, which is not taxable until withdrawn.