The Rule is summed up in the mottoe of the Benedictine Order: ora et labora, "pray and work." The monk or nun's life is divided into regular periods of sleep, prayer, rest, and physical labor. In later periods intellectual work and teaching took the place of farming, crafts, or other forms of manual labor for many - if not most - Christian monastics.
Other rules were written by or are attributed to major monastic founders -- the Rule of St. Pachomius and the Rule of St. Basil in Eastern Orthodoxy and the rules of other western orders.
The Benedictine Order, like any organization that lasts more than 1500 years, has had high and low points. In any moment of reform dynamic Benedictine leaders turn back to a life as close to that of the Rule as they can manage.