The safe and reliable implementation of seismic isolation distinctly requires the thorough qualification of the manufacturer’s fabrication procedures and the characterization of the isolators’ ultimate capacities and dynamic properties through comprehensive testing. Therefore, since the re-invention and patenting of the friction pendulum technology by Earthquake Protection Systems, Inc. (EPS) nearly 40 years ago, over 50 comprehensive isolator test programs for EPS-engineered isolators have been carried out at over a dozen independent laboratories around the world, as well as EPS’ in-house testing facilities featuring the world’s largest isolator test machine. These test programs on single- and multi-spherical bearings with adaptive behavior, briefly summarized in the current paper, included real-time lateral load tests on numerous isolator models to determine isolator properties and capacities for a range of design parameters, shake table tests at full scale and at a scale no less than 1:4, and other system and material tests. The broad qualification testing of EPS seismic isolators and manufacturing processes have remained unsurpassed in breadth and levels of gravity and seismic demands, and have achieved a thorough assessment of key phenomena affecting isolator stability, long-term reliability, and seismic performance.