What is a valid Will?
No Will shall be valid unless: The WILL is signed at the end thereof by the Testator in the presence of two competent witnesses (age 14 years and more) present at the same time. If the Will consists of more than one page, each page other than the page on which it ends, is also to be signed by the Testator. Every person of the age of 16 and more may make a Will.

Competency of Persons involved in Execution of a Will

Any person who attests to and signs a Will as a witness or who writes out the WILL or any part thereof in his/her own handwriting, and the person who is the spouse of such a person at the time of the execution of the Will, shall be disqualified from receiving any benefit from that Will.

Notwithstanding the above: A Court may declare a person or his spouse referred to above to be competent to receive a benefit from a Will if the Court is satisfied that that person or his spouse did not defraud or unduly influence the Testator in the execution of the Will.

Revocation of a Will

Any competent Testator is also competent to revoke his Will. A Will takes effect only upon the death of the Testator and hence is revocable up to the time of his death. The most general way of revoking a Will is the execution of a subsequent Will which contains an explicit clause that revokes all previous Wills.
Capacity to Inherit
Children and unborn children:

Any benefit allocated to the children of a Testator in his Will shall vest in the children of that Testator who are alive at the time of the devolution of the benefit, or who have already been conceived at the time and who are later born alive.

Adopted Children:

An Adopted child shall be regarded as being born from his adoptive parents for the purpose of a Will and not as a child of his natural parents.

Born out of wedlock:

The fact that a person was born out of wedlock shall be ignored in determining his relationship.
What is a Codicil?
A codicil is a schedule or annexure to an existing Will, which is made to supplement or to amend an existing Will. A codicil must comply with the same requirements for a valid Will. A codicil need not be signed by the same witnesses who signed the original Will.

What if I want to amend my Will?

Amendments to a Will can only be made while executing a Will or after the date of execution of the Will. Amendments to a Will must comply with the same requirements for a valid Will. When amending a Will, the same witnesses who signed the original Will need not to sign it.

Must I amend my Will after a Divorce?

A bequest made to your divorced spouse in your Will, which was made prior to your divorce, will not necessarily fall away after divorce. The Wills Act stipulates that, except where you expressly provide otherwise, a bequest made to your divorced spouse will be deemed to have been revoked if you die within three months of the divorce. This provision is to allow a divorced person a period of three months to amend his/her Will, after the trauma of a divorce. Should you however fail to amend your Will within three months after your divorce, the deemed revocation rule will fall away, and your divorced spouse will benefit as stipulated in the Will.
Nomination of an Executor
The Testator may nominate anybody to the Executor of his Estate. Event the heirs of the Testator may be nominated and appointed as Executors. The Executor or his agent has to administer the deceased's estate. He does this under the supervision of the Master of the High Court. Certain persons are not qualified to be appointed as executors i.e. a minor or a person suffering from a mental illness or a murderer.

What if there's no Will?

The pitfalls and implications of dying without leaving a valid Will cannot be emphasised enough , specifically the fact that a Will encompasses the deceased's wishes insofar as the distribution of his /her estate is concerned. The only way for a person to ensure their wishes are carried out on death is through the mechanism of a Will.

Where a person dies without a valid last Will and testament, this is known as Intestate Succession. The Intestate Succession Act 81 of 1987 contains the provisions in terms of which an intestate person's estate is to be divided.