A will is simply a written directive to the probate court as to how property is to be distributed at death, who should be the personal representative (previously called an executor) to manage the estate, and who should be the guardian of minor children. Wills do not get rid of the need for probate. Rather, they plan for the process necessary to put wills into effect. They also provide no protection against incapacity.
A simple will passes the assets to a named individual or individuals and generally contains no tax planning trust provisions or testamentary trusts for minors. The usual simple will is set up to distribute to the survivor of the couple and then, after the death of the survivor, to the children equally.
A complex will contains testamentary trust provisions. It creates a trust at the death of the testator (the person making the will) which may help avoid taxes and provide for a delay in distributions, among other things not covered in a simple will alone. Given its extensive nature, it’s unsurprising the complex will is the most popular type of will.
A pourover will is used in conjunction with a living trust. It acts as a safety net to ensure that the testator’s wishes as set forth in the trust are carried out, even if the assets are not placed in the trust. Ideally a pourover will sits dormant and is never used.