"How long does a power of attorney stay in effect? Does it have to be recorded with the county?"
The duration of a power may be governed by the power of attorney itself. For example, the power may say that it becomes void 5 years (or any number) after it is signed. Its possible that a particular state's laws might create a time frame, but we're not aware of any. The problem with any time limit is that if you don't sign a new power, or you become disabled in the interim, you may be left with no planning. On the other hand, too many people sign and even circulate powers, and years later when they no longer have a relationship with the person named agent (or worse) the powers are still in the hands of now adverse people.