18/6 vs 24/0

Just like thhe title says, how much light would be the optiomal in the start to start growing for photoperiods, or is there such thing? I've always used 18/6, but i've seen people using 20/4 or even 24 hours at the start. I'm already at the second week with 18/6 and they seem to be at least...

18/6 Pros For hot climates, the ability to turn off lights during 6 hottest hours of the day Uses 25% less electricity than 24 hours of light a day (which adds up if you have expensive electricity) Plants are harder to stress and recover faster from problems. Often the grow light can be kept...