I guess it comes down to if you have zero experience in wiring electrical equipment or cannot find a business to do it for you, just get the premade stuff and avoid the hassle. A lot of us have years of experience doing wiring and plumbing and husbandry control through similar experience in jobs or from many years of being in this or the aquarium hobby. It is nothing to be ashamed of being uncomfortable DIYing something and far better to just get it already made than save a buck and end up frying yourself in the process.