Sleep before you learn, not just after
A short night ahead of studying costs you the encoding, not just the recall.
Do this
Protect sleep on the nights before demanding learning, not only after. If a night has been lost, prioritise review of familiar material over acquiring new material that day.
Why it works
Sleep deprivation impairs hippocampal encoding, so material studied while sleep-deprived is laid down worse in the first place. Sleep after learning then consolidates it. Both directions have experimental support, and the pre-learning effect is the one people neglect.
Where it fails
Naps help but do not fully substitute for a night. And this does not license fatalism - studying tired is worse than studying rested, and much better than not studying.
How you’ll know
Compare recall a week later for material learned rested versus material learned after a short night. The gap is usually obvious.