Bandwidth mechanisms and successive channel reservation access within multiple user, multiple access, and/or MIMO wireless communications. A management frame, communicated from one wireless communication devices to one or more others, includes successive channel reservation assignment therein, and also indicates channel(s) within cluster(s) for use in respective communications (e.g., transmissions/receptions) of those wireless communication device(s) that receive the management frame. Subsequent management frames can modify or update such a channel assignment. Channel reservation for use in communications by respective wireless communication devices may be grown when additional channels may become available. Based on later determined information regarding the channel availability status, such channels that may become available can be used for subsequent, wider bandwidth communications. All communications include a primary channel (as indicated by a management frame, prior control frame, or other means) that may be located at a band edge or between respective channels (e.g., not at a band edge).