I think it depends on how you define 'consistent'. A schedule where I go to sleep at the same time every day doesn't work for me and never has - it's precisely

I think it depends on how you define 'consistent'. A schedule where I go to sleep at the same time every day doesn't work for me and never has - it's precisely that which turns me into a walking zombie, as I've been for most of my time in high school. Instead, I generally just go to sleep when I'm tired and wake up naturally when I'm done sleeping. This automatically falls into a pattern where my bedtime shifts forward by 1-2 hours a day, in a cycle. Whenever I can follow that pattern, I sleep and perform extremely well. Different people still do appear to have different optimal sleeping patterns.