We always tell people to consider updating their will if one of the “major players” dies, becomes incapacitated or estranged. In other words, if a named beneficiary (someone who is inheriting), an executor (person who will manage the distribution of the estate) or a trustee (person who you have named to manage a trust) cannot do whatever it is you anticipated them doing (whether it is inheriting property or managing the distribution of your estate), then you need to look at the will and figure out how things will work without that person’s involvement. Then you can decide if your will needs to be updated.
Since probate law varies by state, if you move to another state you should execute a new will there.
If you add a child to your family and your will does not provide for that event, you should update your will.
You also may wish to add make specific provisions for your grandchildren.
If you become aware of a change in state or federal law that may affect your estate, contact an attorney to see if you need an update.
If you have a significant change in your financial status, you should re-evaluate and update your will.