With the development of social economy, people accumulate more and more private property through labor. However, people always die, and their property will be preserved in the society. How to arrange the inheritance properly before death is a problem that many people consider. Making a will before death is an effective means to properly arrange things and property.
 The effect of a will is different in different ways. To discuss the validity of wills, we should first understand the classification of wills:
 Wills are divided into: self written wills, written wills, recorded wills, oral wills and notarial wills.
 A handwritten will is a kind of self written will. A self written will is written by the testator in his own hand, signed, and marked with the next year, month, and day. In the form of testament, self written testament, written testament on behalf of others, recorded testament, oral testament, if the contents of several testaments contradict each other, the last one shall prevail. However, if it is a notarial will, a self written will, a written will, a recorded will, or an oral will, the contents of the notarial will cannot be revoked. If the notarized will wants to change the content of the will, a second notarized will needs to be made.
 Article 17 of the Inheritance Law of the People's Republic of China
 A self written will shall be written and signed by the testator, and shall be marked with the following year, month and day.