Building control panels is easier using modern wiring duct. Using duct
became popular for a professional appearance and efficient wire
connection changes. More recent wiring duct options save panel space. Running
out of space can destroy hours of labor. Yes, you should lay out all
the components before ordering the box, but sometimes you have last
minute additions. Maybe you have limits on wall space to mount the
enclosure. Larger enclosures cost more, even if you have the space.