People who are doing their estate planning, and some of the professionals that advise them, often assume that, if a person has a power of attorney for their spouse or loved one, and if it has been properly executed, they are covered for anything that they might need to do for that spouse or loved one, should they become disabled. This assumption can sometimes lead to problems down the road.
Powers of attorney are not one-size-fits-all types of documents. The extent of the powers that are held by the attorney in fact (the person who is able to act on behalf of the individual who executed the document) are defined by the document itself. Some documents draw those powers very broadly, and some very narrowly. If the power of attorney doesn't have enough "punch" in it, it is possible that it won't be as useful as you want it to be several months or years down the road when it is needed.
The most common example of this problem arises in long-term care planning. Often, when engaging in long-term care planning for a disabled individual, it becomes necessary for the disabled individual to give away some of their money or property. If that person isn't competent to sign the documents necessary for the gifting themselves, and if the power of attorney doesn't allow for gifting, then it may become more difficult, time consuming, and expensive to continue with the planning process.
I practice in Abilene, Texas, which means that my clients live in a state that makes available a "form" power of attorney, which we call a "statutory power of attorney." That power of attorney can be useful for people who need them, but it is limited in its effectiveness. My experience has been that, when preparing those powers of attorney, I will often need to modify them - sometimes heavily - to make sure that we have explicitly provided to the client all of the powers that might be needed by the attorney in fact when the client becomes disabled.
If you (or your customer/client) have someone that they can trust to take care of their financial affairs, then they should definitely have a power of attorney, regardless of their age or place in life. However, it is also important to make sure that the power of attorney contains all of the right terms, and to get that assistance, it may be important to consult with an attorney who is familiar with the kinds of powers that will be needed down the road.
The good news is that most attorneys, like me, will include powers of attorney as a part of their standard estate planning packages, so you can often get your will, a good power of attorney, and your health care power of attorney all done at the same time.