Whenever I'm up in the tower late at night, waiting for an air ambulance to return for hours and hours . .
i switch from headset to loudspeaker, put volume to max on twr & app freqs and wait in "relaxed" mode.
I do try not to sleep, but its not that easy when i'm working alone on tower and approach for up to 16 hours (split shifts) on some days.
I'd rather be fully awake for the approach and landing phase, and do it right, than half asleep.. forget rwy inspection.. forget atis.. you get the picture.