LEACH-like clustering protocols focus mainly on the low-power, low-rate, and low-wakeup network applications, and work in a multi-round clustering strategy that causes frequent handovers of cluster heads, thus less support for real-time services which require stable cluster topologies. Besides, these protocols are faced with respective drawbacks such as sub-optimality of selected heads, costly node-BS (base station) energy overheads, lack of runtime cluster maintenance, etc. This paper proposes RANCE, a randomly centralized and on-demand clustering protocol, aiming at prolonging nodes’ clustered time to support inter-nodes collaboration while being energy efficient in mobile ad hoc networks. First, RANCE designs a randomly centralized cluster head selection mechanism in which every node in the local wireless network is eligible to initiate the centralized cluster head selection, so that the self-organizing characteristics of mobile ad hoc nodes can be utilized for head selection optimization. Second, taking into account the wireless volatility caused by changes of topology, obstacles, signal strength, etc., the fine-grained cluster relationships maintenance is provided by means of multi-level aliveness and adaptive bidirectional heartbeat packets. Third, RANCE works in an event-driven and on-demand manner instead of a time-triggered manner in LEACH-like protocols, to reduce the impact on continuous services caused by frequent cluster head handovers among all nodes. Simulation results show that RANCE provides longer clustered time (over 99% of nodes’ lifetime in networks more than 100 nodes) and good clustering scalability with high consistency at minimum energy cost, and exhibits good potentials in mobile wireless environments that are infrastructure-less/poor for continuous missions. Author