Rule #3: Always keep the control panel you are working on nice and clean.
I'm sure you have been to the field to service a control system, open the panel and it looks like a rats nest of wires and cables. One contributing factor to this is "Not my job" mentality. One tech comes out, leaves the panel a mess because he was in a hurry or just did not care, the next person to service the panel more than likely isn't going to clean it up and it just keeps getting worse with every servicing. Maybe you are thinking, "Well I'm not being paid to clean the panel up, just to get it working again" , cant blame you for that. However, you can leave it in a better condition than how you found it, that's a start.
Another contributing factor to panels like the one above, is how it looks after it was initially built and installed. You can tell by the uneven door jumper sizes and the lazy way the wires are routed that this panel did NOT look good to begin with. So why would the technician servicing this panel in the future care to make it look better than how he/she found it? The answer is they will not and the panel will just snowball as more people service it. The solution to this is to never accept a poorly wired panel EVER. If your the person building the panel then its your job to produce an acceptable product, your job could and should be riding on how well they look when finished. Its harder to leave a great looking panel messy. Easy to leave a messy panel worse than you found it.
Another factor that plays a big part in the state of a panel is the initial design. As you can see in the above picture, the top wireway size spec did not take into account the number and gauge of the wires and cables that would be run into the panel. Thus the covers are left off and there is no attempt to route the wires and cables properly into the wireway.
Here is another example, a control cabinet that has been continually updated through the years. Equipment being abandoned, wires cut and left in the panel.
This is a before and after picture of a control system ACI did for city water distribution. On the left, you can see how wireway covers have been left off or are just plain missing, lazily routed wires and cables, unlabeled terminations, unmanaged cable bundles going to door hardware, just to point out a few problems. The drawings and documentation were also incomplete, or just printouts of pictures with hand written notes on them (see picture taped to door on left side). This made servicing and troubleshooting a nightmare and doubled the required time needed to complete
On the right hand side, you will see the three panels ACI built and installed to replace what was previously there. Notice the wireway covers all in place, all terminations labeled, correctly routed wires and cables with spiral wrap when required. No more need for that huge device on the door so that was removed completely and covered with a metal plate. Also, every device and wire/cable termination point is documented on the drawings. The service tech can open the cabinet, find the sensor termination point on the drawings, immediately locate and begin troubleshooting.
It all boils down to how well the panel was designed and built. Bad design and poorly terminated panels will ALWAYS turn out like a rats nest down the road. If there was no pride and craftsmanship that went into the panel initially, then there never will be from anyone else.