You might think that estate planning would be easy when couples don’t have children. In fact, it can sometimes be more difficult – and also more important.

Couples with children generally agree about passing on their assets to their kids, and can rely on their offspring to serve as caregivers and executors. It might not be so easy for other couples.

For instance, suppose Mike and Helen write a will leaving their assets to each other. If Mike dies first, Helen will inherit everything. When Helen dies, who will get Mike’s assets? Helen could make a new will, but if she doesn’t, all of Mike’s assets will go to Helen’s relatives according to state law.

But what about Mike’s relatives? They would be left with nothing. And the same is true for Helen’s relatives if she happened to die first.

Of course, Mike and Helen could agree that the surviving spouse will sign a new will that’s fair to both families. But what if the surviving spouse gets remarried, or has a falling out with the in-laws, or dies shortly afterward, or is elderly and simply doesn’t get around to it?

A better approach might be for Mike and Helen’s will to say that if one dies, his or her assets will go into a trust. The trust can benefit the surviving spouse during his or her lifetime, and then go to the other spouse’s family. That solves the problem.

Another issue is who will serve as power of attorney or health care proxy. If Mike and Helen name each other, and one dies, who will be listed as the alternate for the surviving spouse? If there are no children in the picture, this requires very careful consideration.