>Even if they use a shitty cable you can pull your own cable through after the fact, no? Often you can't use the old (unwanted) cable to act as a "fish tape"

>Even if they use a shitty cable you can pull your own cable through after the fact, no? Often you can't use the old (unwanted) cable to act as a "fish tape" or "mouse" to pull a new cable because the old cable is routed through many small holes in 2x4 studs, ceiling plates, or joists. The path usually has several tight 90 degree turns, with staples, and some of the holes are even spray foamed. There would be too much friction inside the walls to pull a cable for non-trivial distances. If the old cable was inside of conduit, pulling a new cable could work but that type of install is very rare. Conduit for networking cable is typically only used underground to bury the cable between buildings rather than inside the walls of a single home.