Endface geometry specifications are critical to the long-term reliability of the network. If the fiber height is too large, mating two connectors together could result in the fibers being in stress when in contact, resulting in damage that can impede transmission and cause a network failure over time as the epoxy bonds break down. If the fiber height is too small, or undercut, then physical contact will not be made, which can increase back reflection and lead to laser destabilization. Although these parameters are critical to the reliable operation of a network, it is difficult to determine if terminations are meeting those specifications without the correct equipment.

End face quality is equally as critical. Pits and scratches on a fiber weaken the surface of the glass, decreasing its ability to withstand stress and environmental changes. In addition, pits and scratches serve as reservoirs for contaminants. These  have serious ramifications for network reliability

How can you be sure that the cables you purchase from your supplier will not be subject to these failures??