Someone asked: if I meditate but end up falling asleep, do I still gain extra merit?

Understand that falling asleep happens because the unwholesome seizes the opportunity, overlaying a sphere of torpor and drowsiness — dullness, confusion, sleepiness — as an unwholesome sphere. While we're asleep, we can't draw in merit during that time. But the unwholesome itself must spend its own energy to keep imposing this state on us, and that energy gradually depletes until it runs out. Once the impurity has been used up, we wake up naturally and can resume practice. So there's no need to worry — sleep when sleepy, that's fine, since the impurity is forcing drowsiness on us. This drowsiness arises from the mind's darkness getting entangled with sensual desire — attractive sights, tastes, smells, sounds, and touches — becoming impurities that manifest as the hindrances, causing sleepiness, dullness, or restlessness. But once spent, they're gone — just don't go seeking out those pleasurable things again, adding fresh impurity.