alt Hacker NewsIMO developing good sleep hygiene is by far the most important habit to cultivate.
It has lots of benefits, but the most important one is it replenishes your willpower. If you're trying to develop other healthy habits, it's 10x harder if you haven't slept well.
It's also the easiest to implement, imo. But there is a tradeoff: fewer waking hours during your best years cognitively for more years when you're older...