A joint will is a single will that’s signed by two people, usually a married couple, leaving all their assets to each other. Seems simple and sensible—but it’s almost always a bad idea. If you’re an executor, the good news is that you’re unlikely to have to deal with a joint will, because these days they’re very seldom used.

What Is a Joint Will?

Typically, a joint will provides that:

• when one spouse dies, the survivor will inherit everything, and
• when the second spouse dies, everything will go to the children.

Most joint wills also contains a provision stating that neither spouse can change or revoke the will alone—which means that the will can’t be changed after the first spouse dies. A conventional will is always revocable. But a joint will is really a binding legal contract, which cannot be revoked or changed after one spouse has died.

A joint will appears to both fulfill many couples’ wishes and address some of their key concerns. First, as many couples want, it provides that the survivor will inherit all the property of the first spouse to die. Second, it’s then assured that no matter what happens after that, the children will eventually inherit everything. For example, if the survivor remarried, the children wouldn’t have to worry that their inheritance would go to their new stepparent. Instead, because the terms of the joint will would be locked in, they would be guaranteed to inherit.

Potential Problems With Joint Wills

Today, estate planning lawyers advise against joint wills, and they are rarely used. The reason is that making it impossible for the surviving spouse to change the terms of the will can turn out to be a very bad result. The survivor—who may live years or decades after the first spouse’s death—cannot react to changed life circumstances, and the family may suffer as a result.

For example, the survivor might not be able to:

• Give an adult child some of his inheritance early—perhaps to buy a house or start a business
• Help grandchildren with college expenses
• Put restrictions on the money that will be inherited by a child who is financially irresponsible
• Sell the family home and buy something smaller, or move into an assisted living facility
• Sell or give away other assets covered by the will

There can also be estate tax complications if the estate is very large.

Some states (Wisconsin, for example), do not allow joint wills. If presented with a joint will, a probate court will try to separate the document into two separate wills. If the document is written in a way that it can only become effective when the second spouse dies, the court will refuse to admit it to probate.

Alternatives to a Joint Will

Fortunately, there are other ways in which couples who want to be sure that their children—and not some possible future second wife or husband—will eventually inherit the family wealth can accomplish this goal. They don’t need to resort to an inflexible joint will. For example, parents can set up a trust, attaching whatever restrictions they wish on the surviving spouse’s use of the property, who manages the money, and when the children receive it.

Getting Legal Advice

If you're trying to create your estate plan and are considering a joint will, talk to an estate planning lawyer first. If you’re an executor and find yourself dealing with a joint will, talk to an experienced probate lawyer. These wills can raise many questions, and you’ll need to proceed carefully.