Many factors affect the answer to the question.
We have a small non profit association and are trying to locate information on whether or not we have to have a Board of Directors. We are not incorporated. Others do not. It is my impression that many states and localities make no special effort to deal with very small organizations, especially those where there is little or no financial activity. If the leadership of the organization is willing to go forward without the protections and guidance of the corporate form, and if there's not a lot of money changing hands, you can probably operate indefinitely without encountering any external requirements.