(1) When properly selected and applied, flexible disc couplings can run for a very long period of time with often described as an infinite life. For example, many disc couplings run for decades without requiring service.
(2)Flexible disc couplings are non-lubricated, so maintenance is not required to re-lubricate the coupling assembly. Since there is no lubricant, flexible disc couplings avoid the mess that can result from maintaining or running a greased coupling.
(3) Flexible disc couplings can be designed with relatively tight tolerances to provide a well balanced coupling assembly. A well balanced coupling has a low magnitude of imbalance.
(4) Imbalance is inherent in every coupling assembly. The imbalance will create a radial force when the coupling is rotated. The magnitude of the force increases as the rotating speed (RPM) increases. The relationship of the radial force to the rotating speed is a squared function. In other words, doubling the speed results in four times the radial force, and tripling the speed results in nine times the radial force.
(5) In the unlikely event of a fracture, flexible disc couplings are generally expected to fracture in a progressive manner beginning at the outer disc of the disc pack. When this occurs, the coupling will run and perform with almost no loss of function. The fracture may eventually progress into the subsequent discs. Most often the progression of the fractures becomes evident during a visual inspection. Alternately, there would be a noticeable increase in vibration. In critical applications, a vibration sensor can be used to automatically shut down the equipment.
(6) Flexible disc couplings may be visually inspected to observe the flexible disc and hardware by removing the guard and observing the components. This inspection is best performed when the rotation is stopped and the guard is removed. A strobe light can be used to inspect a rotating coupling, and care should be exercised and safety should be evaluated before approaching any rotating assembly.

Flexible disc packs are comprised of thin sheet metal shims, stamped or laser cut in a ring shape with a series of mounting holes; commonly 6-8 but more or fewer are also used, depending on the size of the coupling, with the smallest commonly using four and with any number of holes for the very most significant sizes. 

The shims are stacked together and held in place by bushings, and the resulting disc pack is bolted into the coupling system. Misalignment compensation depends on the flexibility of the shims themselves. Generally, the larger the stack, the greater the overall stiffness of the disc pack in terms of both torsion and bending. 

Centering of the disc pack in the coupling can be accomplished by different means. One standard method is precision machined pockets in the adjacent mounting flanges, which hold the disc packs concentrically in place by their bushings.  The disc packs are mounted to their respective hubs with the bolted joints alternating between the driving hub and the driven hub.