Have an early/a late night
Definition 1 of 2
Pro Tip 1/3Rest Preparation
Used when emphasizing the need for rest before an important event. 
She decided to have an early night to be fresh for the interview.
Pro Tip 2/3Health Conscious
Implies caring for one's health by avoiding late nights. 
He has an early night every Friday to recover from the week.
Pro Tip 3/3Routine Disruption
Suggests a break from the usual sleep-wake cycle for specific reasons. 
After the long flight, I'm having an early night to reset my clock.