Back row of ribbon cables tend to go first -- normally due to people pulling on the cable rather than the plug (human nature to go the easy route). Usually one of the two back corners will go intermittent first.

Adding a strain relief will add life to the cable. Some cables don't have real good strain reliefs and they tend to come off (I'm looking at YOU - 3M). Many of today's IDC plugs need the strain relief installed as it is an integral part of the plug and helps hold the entire shooting match together. This includes the popular "FC" series plugs made by practically everybody. These are sold under a myriad of part numbers - look for "FC26" (26 pin) or "FC20" (20 pin) on back under strain relief. Keying is not required for any of these plugs - none of the manufacturers used keyed sockets.

Making ribbon cables is not difficult but is a time consuming task. Helps tremendously to have the correct tools --> platen type ribbon cable cutter and a good 3M ribbon cable press with proper platen.

I had considered DE ribbon cables in the past but I don't have any experience with DE machines. Ribbon cables are so time consuming that I'm glad to see another person taking up this line.

I can make most cable but don't have a list compiled for the earlier machines with pin counts, lengths, etc.