Large-scale research and testing in the area of energy conversion become a fundamental necessity during the current national effort to commercialize proven processes that have been dormant for many years. A recent example of such necessity is the on-site use of a 1-MWe ocean thermal energy conversion (OTEC) system where ocean temperatures are suitable for energy extraction. Other experimental examples are the coal liquefaction plants currently under construction, as well as many first-of-their-kind syngas systems and “combined cycle“power-generating loops. The large investment in such research design and development projects is further extended by the cost of operation, where budget limitation may force the preclusion of certain test objectives or the premature termination of ongoing test programs. To reduce the probability of such happenings, optimal test programs need to be devised and implemented. This article deals with various aspects of such testing optimization. It is hoped that some of the stated opinions or cited experience will be considered by planners of large experiments so that costly and irretrievable operation time may be utilized for maximum results.