A will is a legal document that lets you tell the world who should receive which of your assets after your death. It also allows you to name guardians for any dependent children. Without a will, the courts decide what happens to your assets and who is responsible for your kids.
Wills do have limitations. In particular, the beneficiary designations on financial accounts, insurance policies and other assets take precedence over wills, so it's important to make sure your beneficiary designations are up to date and reflect your wishes.
For example, say you list your husband as the primary beneficiary on your retirement plan at work, but then you get divorced and marry someone else. If your first husband is listed as the account beneficiary, he will receive those assets at your death - even if your will says otherwise.
A will also allows you to name your executor, the person who will be in charge of your estate. Before you select an executor, make sure you understand the tasks he or she will need to perform, which include distributing your property, filing tax returns and processing claims from creditors. Your executor should be someone you trust completely - and don't forget to ask if he or she is willing to take on such a big responsibility.