To ensure your will stands up it should be written by an attorney. Wills that you write yourself, or fill-in-the-blank preprinted wills, may not cover all of your particular circumstances. Generally, you and your spouse should have individual wills rather than joint wills, for more flexibility.

Be specific in your bequests. Don’t assume that your son knows that he’s to receive your stamp collection and your sister knows she’ll inherit your pearls. Spell out those bequests with enough detail so there’s no confusion. Don’t make bequests such as, “the contents of the desk in my home office go to Phyllis,” because you don’t know what will be there at some future time.

Another good tactic is a “residuary” clause, a clause that states that anything not specifically mentioned in your will goes to your spouse or to someone else. Again, that will help reduce confusion.

At the end of the document, restate for the record that this is your last will, consisting of a certain number of pages. Make sure that the pages are numbered and that you initial each one. Get at least three people who aren’t beneficiaries to act as witnesses, making sure to include their addresses as well.

Keep in mind that your last will probably won’t be the final word. At certain points in your life, your will should be amended. Births (of relatives) and deaths (of anyone named in your will) may require new wills. The same is true if you move to a new state, where the laws may be different.

In addition, you probably will want to change your will if your economic circumstances change significantly; you might inherit assets from your parents, for example. Changes in federal estate tax law might make a new will desirable.

Review your will every two years to see if it still reflects your present circumstances. When it’s time for a change, you may have to completely re-write it or you might merely amend it by a slight modification, called a codicil. Again, consult with an attorney.