The placement of operating cables varies a little for extension systems and torsion systems, however the functions are the same: to provide the counterbalance strength to open and close the door. Extension operating cables run vertically on each side of the door, and horizontally to connect to the extension spring. Torsion operating cables run vertically down the length of the door. The weight and frequency of use of your door as well as the type of pulley used can shorten the lifespan of your cables.
Good: Standard operating cables have 7 wires per strand and 7 strands per cable.
Best: Aircraft quality cables have almost 3x the amount of wires with 7 wires per strand and 19 strands per cable, increasing the durability and strength of the cables.