I had a gig with a secondary band (for all players, who all have at least 1 other "primary" bands) over the weekend. One of the members recently dropped some serious money on new PA gear: Presonus 1602 mixer, a bunch of powered mains/monitors/subwoofer. Starting to cable everything up, PA owner reveals that he has every cable labelled on each end, which unit/channel/jack to plug into. I had never worked on this particular system, but I have a good working understanding of how systems work in general. By the time each cable was identified, run, re-run, swapped for the "correct" cable, etc. I have no doubt that I could have gotten that system set up & running in about 1/3 the time! It's one thing to have a convenient "map" to follow, to make sure that everything is connected & "works" right the first time. The trouble is, if you're completely dependent on your map, it's hard to navigate when the "terrain" changes & the map no longer applies - and in my experience, at least, exceptions seem to be more common than "typical" setups. My preference is to understand the system as completely as possible & carry a good supply of adapters, cables of varying lengths, etc. that I can make a system work in a variety of venue sizes, configurations, added or deleted gear, etc. Obviously, though, there is at least one other way of doing things.