Such persons form a stable part of the community. In contrast to young families which are often compelled to move as their families grow or their jobs change, the elderly set their roots fast in the community, usually for the rest of the span of their lives. They have no need for schools and related services, nor do they require, in the aggregate, as many municipal services and facilities. The taxes paid by them, directly or indirectly, help to stabilize the tax base required to provide schools and other public services in those areas and for those land uses which require them. Usually having a greater than average purchasing power, they bolster the local economy. Moreover, a minimum amount of retail trade and services, professional and otherwise, may be carried on in such a specialized development for the convenience of its inhabitants, some of whom will, by reason of age or reduced physical fitness, be unable to travel easily. Such accessory uses may also diminish the amount of vehicular movement generated by such community, thereby promoting its tranquillity.