All states require you to be of “sound mind” when making your will. Though the exact language varies, you must essentially have an understanding of what you are doing. But the threshold of that understanding is not very high, and the mental capacity necessary to make and sign a will is significantly less than that required for other legal documents.
Most states require that you be at least 18 years of age to make a will, but there are exceptions. For instance, in Georgia, you must only be 14, and some states allow persons younger than 18 to make a will if they are or were married or are in the armed forces.
Almost all states require that wills be in writing, but some accept nuncupative, or oral, wills, as well. Also called deathbed wills, testators speak them aloud to two witnesses when death is imminent. Most states that do accept these wills limit the amount of property transferred this way. Some limit who can make them. For instance, in New York, only members of the armed forces and merchant marines can bequeath property this way. As of 2010, 26 states also accept holographic, or entirely handwritten, wills -- with varying requirements regarding witnesses -- if they are written in the testator’s own handwriting.
As of 2010, all states except Georgia protect spouses from disinheritance through “elective share” laws. If you leave your spouse out of your will, either intentionally or by not updating it after you marry, he is entitled to instead elect to take a percentage of your estate determined by the laws where you live. In some states it is half of your estate, and in others it is one-third.
Most states allow you to disinherit a child, but also have laws that give your child a portion of your estate if you disinherit her simply by omitting her from your will or if you die without making one. If this is your intention, state the name of your child and your specific wish that she not inherit from you to avoid her contesting your will later.
Revocation by Marriage or Divorce
If you neglect to update your will or make a new one after you divorce, most states protect you against your spouse inheriting anyway by extinguishing all bequests to him and appointment as executor as of the date of your divorce decree. The exception is if you specifically state in your will that you want him to inherit anyway. Some states also nullify or revoke your will if you marry after making it if you don’t state your intention to marry anywhere in its terms. However, elective share laws would cover your new spouse in this event.