Most Wills (or Trusts) created for individuals who own significant assets provide for "Descendant's Trusts" for children, grandchildren and other descendants. Some Wills include "Child's Trusts" for children only. Others include Child's Trusts for children and Descendant's Trusts for grandchildren and other descendants. Both trusts for children and trusts for grandchildren and other descendants can be called, "Descendant's Trusts." In any case, each child or other descendant is the named primary beneficiary of his/her own separate trust. The beneficiary's own children and other descendants are often included as additional (secondary) beneficiaries of the beneficiary's trust to whom distributions can be made while the primary beneficiary is living. This adds flexibility and increases the income tax options. When the primary beneficiary dies, the assets remaining in his/her Descendant's Trust will usually be distributed to new Descendant's Trusts for his/her children, but it is typical to give the primary beneficiary of a Descendant's Trust a testamentary power of appointment (see below).

In Wills without second generation planning, "Contingent Trusts" are used. Contingent Trusts terminate when the beneficiary reaches the specified age (such as age 25), but it is also common for a Contingent Trust to have multiple staged terminations (e.g., 1⁄3 at age 25, 1⁄2 of the balance at age 30, and the balance at age 35). If the beneficiary dies prematurely, the remaining assets in his/her Contingent Trust will be distributed to his/her children, if any, otherwise to his/her siblings. Until the time that the Contingent Trust terminates, the trust protects the beneficiary, just like a Descendant's Trust. However, when a Contingent Trust terminates, all of these protections are lost.