I went with one of my engineers to meet a potential customer in Houston. They needed a system upgrade, but first they had an earnings call coming up, and the current system had to work for it.
There was a set of line drawings on the wall of the MDF, marked "as-built" but it was woefully inaccurate. The equipment in the rack did not line up with the drawings, and very few of the cable labels agreed with what we found. It took a week of toning wires and testing equipment to understand the system well enough to get them through the call. That week paid off, because our upgrade proposal was built on facts. It also should never have been necessary.
Closeout documentation is the unglamorous part of this industry. As-built drawings, IP spreadsheets, setup files, and patch panel layouts take hours of engineering and PM time, and nobody gets into AV to build giant documentation packets. For an integrator that expects to support the system anyway, the packet is an easy place to save cost. It gets done thin, or it is the design set with a new title block, and it is out of date the day it is handed over. The packet tends to be written for whoever signs the final pay application, when the person who needs it is the technician opening the rack years later.
For the first year, nobody notices. Then someone on the customer side leaves, and their knowledge of the system goes with them. Then someone on the integrator side leaves. Two years later something fails, and the service team arrives knowing nothing about the job, or worse, trusting drawings that are wrong.
At Ford AV, we deliver our closeout packages electronically and keep them in the cloud, as much for our own service engineers as for the customer. When they arrive on site, they can find current as-builts, firmware revisions, IP spreadsheets, and code in minutes.
Keeping those documents current is the hard part. We try to capture changes as they happen, including the ones the customer's own team makes, and even our best effort misses some.
If you are buying a system, ask to see a sample closeout package before you sign. Then hold the final invoice until yours includes as-builts that match the rack, the IP spreadsheet, and every setup file, stored somewhere your own team can reach.