Most of the time, we do better on tasks when we’re most awake. But some problems require a mind that’s just a bit tired—or otherwise impaired, reports The Atlantic.

Wieth cautions that it’s still better to do most types of work at one’s optimal time of day (and, erm, sober.) But people can use this mind hack to their advantage by, say, scheduling time for creative writing in the mornings, if they’re an evening person, or doing some brainstorming late at night, if they’re usually up at dawn.