I did install a switch, just for the option of keeping the lights off 100%, otherwise they only work with the reverse lights,, its one of the little idiot laws here, and happy with the set up.
If I want the lights on for unpacking etc, I just leave it in reverse (manual tranny) and shut the engine off, key in acc. position.
Its a simple install, if you don't want any switch, all the wiring is in the back in one location.