Individuals can incur a tax filing requirement at any age. A minor child who is required to file an income tax return is likely to need some level of assistance and guidance from an adult. Most minor children are included as a dependent on the tax return of a parent or guardian. However, the dependent may have earnings of their own. Because they can be claimed as a dependent on another tax return, the income threshold at which a dependent must file a return is lower than the regular filing threshold for nondependent individuals.