The primary purpose of a Will is to express the Testator's wishes with respect to the transfer of his or her property at the time of death. Every once in a while, a Will does not provide clear enough information to help the Executor or personal representative fully carry out the distribution of the assets of the estate.

For that reason California provides some helpful rules of construction. Here are a couple:

1. Preventing Intestacy: California Probate Code Section 21120 states that: "The words of an instrument are to receive an interpretation that will give every expression some effect, rather than one that will render any of the expressions inoperative. Preference is to be given to an interpretation of an instrument that will prevent intestacy or failure of a transfer, rather than one that will result in an intestacy or failure of a transfer."
2. Revocation of Gifts to Former Spouses: California Probate Code Sections 6122 and 6122.1 provide that gifts made to a former spouse or registered domestic partner are presumed to be revoked unless the Will states otherwise. The law assumes that you would not leave a gift to a former spouse or registered domestic partner if you divorced or ended your domestic partnership. 

A challenge of estate planning is drafting documents in a clear manner so that people in the future don't need a crystal ball to determine your intent. Along a similar vein, Wills and Trusts should be drafted in a way that capture reasonable contingencies that account for changes in your situation and that don't render your Will or Trust ineffective.

For example, you might suggest that a distribution be made to your "then living children" rather than a child who is alive at the time you create your Will. That way, if you have more children in the future, you may not need to amend your Will or Trust to account for later born children. Thinking through these possibilities is something that your estate planning lawyer should help you do.