I think if I were building a new darkroom I'd put one temp controller at the front of the line, because I usually want one temperature at a time (i.e., I don't do color and B&W on the same day). Then let's see--one spigot for handwashing and water for mixing chemicals, one for the washer, one for a running water rinse tray (in place of a stop), and maybe one for a water jacket if needed--4 total, and maybe a fifth for something I haven't considered. It's not too expensive to add faucets when you're installing everything new, so why not?