If someone subscribes to the "I can do better than nature" philosophy (keeping lights on 24 hours to maximize growth relative to time), I'd advise them to look into LED "flower initiators." Hitting plants with 720nm (far red, I forget if it's 720 or 730) puts them into the hormone-producing state faster, allowing you to run something like 14 hours on in flower. More light, more growth, or faster finish.
I'm happy with the results of 18/6 and 12/12. Haven't been tempted to use more electricity to see what I get. I tend to gravitate toward how to use less.