As mentioned above, my builder friends will put in PVC pipe to run cables between floors and in walls. This allows cables to be replaced relatively easily if th

As mentioned above, my builder friends will put in PVC pipe to run cables between floors and in walls. This allows cables to be replaced relatively easily if their time of usefulness is exceeded. This seems to be a common best practice, sort of like blowing in expandable foam insulation between the historic (unchangeable) facade and new inner walls to properly insulate a historic home. Electrical Metallic Tubing (EMT) conduits are similar but more stringent (fire protection). https://en.m.wikipedia.org/wiki/Electrical_conduit https://en.m.wikipedia.org/wiki/Electrical_conduit