Remember when you were in your teens and still driving your parents’s cars? Every Friday night, it was the same routine, “Dad, Mom, can I use the car tonight?” And either the keys would come flying your way–or they wouldn’t. But when they did, you were off in a flash and out for the night.

Did you ever try to take advantage of that permission slip a day or two later? You know, as in, “Well, they gave me permission on Friday, it must be okay today”? I’ll bet you tried something like that at least once. I know I did. What was the result?

For me, it was a lecture and, if I recall correctly, my car privileges were revoked or some such. Why? The conditions that prevailed when my parents gave me the keys on Friday no longer existed on Tuesday. Now, Mom needed one car to go to a church function. Dad needed the other car to do business 20 miles away. In other words, my permission slip had grown stale.

Ever eaten stale food? Last night I cooked some boxed scalloped potatoes that were way past their “best-used-by date,” as in five years past. I can still taste the taste of stale in my mouth. Yuck.

Staleness can be a problem with powers of attorney, living wills, and the like as well. According to Jeremiah Barlow, an attorney with WealthCounsel.com, many financial institutions and hospitals won’t accept a power attorney, living will, and other such document if they’re more than two or three years old because, well, conditions may have changed. The principal–the person granting the power to the agent–may no longer have the need for an agent–the person granted the power–to do things for him. Or he may want someone else to do it.

Or, as the financial institution or hospital may be thinking, maybe the power of attorney or living will has been revoked or changed by the principal.

And so, it’s good practice to update–literally–any of those documents you may have signed years ago. Make them fresh again, so your bank or hospital will accept them. Update them, so they work when they’re supposed to.