Once you've had your will drafted, you may eventually need to have it changed. The question, of course, is: when?
While attorneys do our best to draft wills that are durable and will reflect your wishes in a variety of scenarios (related to who may or may not survive you, who will serve as executor, etc.), your will may need to be updated when 1) your wishes change, 2) your situation changes, or 3) the law changes.
Only you can say when your wished have changed in such a way that your will should be updated. This is usually related to who you wish to give property to or who you want to serve as your executor when you pass. If either of these changes, you'll need to update your will. If the changes are straightforward, you may not need an entirely new will, but can often have an amendment drafted that will be probated with your will called a codicil.
Sometimes your situation can also change in ways not anticipated in your original will. This is usually related to changes in your natural heirs - your immediate family. While we can account for beneficiaries and executors dying, some events are more difficult to plan for, such as divorce or remarriage. If you have a will and you get divorced or remarried, you should know that the law changes how your will will be handled - automatic adjustments are made to reflect for those events. However, those automatic changes do not reflect what most people would want to happen with their estate. If you update your will after either event, or if you will is explicitly written in anticipation of either event, you can avoid those changes and choose what you wish to happen to your property. Depending on how your current will is structured, it may be best to update after having a new child, as well.
Another common situation that would warrant a review or update to your will is when a law changes in a way that impacts how you wish to handle your estate. A somewhat recent example is the change to estate tax law that went into effect in 2011. Previously, many people used complicated marital trust schemes to minimize estate taxes paid by the couple, where today the need for such trusts has been eliminated for most families. Additionally, if you've moved from one state to another since your will was drafted, differences in state law may affect specific provisions of your will. But because most people don't keep up with changes to the law that may warrant changes to their will, the safest route to take here is if you've moved to another state or if your will is very old, making changes to the law more likely.
As a rule of thumb, some of the most common situations that are most likely to warrant a change to your will include:
1) Desired changes in beneficiaries;
2) Desired changes in executors;
3) Marriage or divorce;
4) Relevant changes in the law;
5) Moving out of state; and
6) A very old will.
After review by an attorney, you may or may not need to have your plans revised. The best policy is that when in doubt, speak to an attorney and have your current documents reviewed.