The answer to the question “How much testing is enough?” is still hotly debated within the test and evaluation community 25 years after the Military Operations Research Society and the International Test and Evaluation Association co-sponsored a mini-symposium on the topic in 1994. The intervening years have seen substantial progress in areas like the use of experimental design for sizing tests, combining data from developmental and operational test to improve efficiency, and the wide-spread adoption of modeling and simulation in test and evaluation. Less progress has been made in cost transparency and integration of technology demonstrations with the test and evaluation process.