Do you wake your newborn to eat every 2-3 hours or just feed on demand?

Andrea • 4-26-16 💙
I have heard of people doing both, so I just wanted to hear what you guys are doing. I was told to feed my baby every 2-3 hours and wake him if he is asleep. So I've been setting alarms and doing so but sometimes he is so sleepy to even eat and falls asleep while nursing. Would a longer stretch of sleep (such as 4 hours) once per day (like at night time) hurt him? He is gaining weight just fine, has plenty of pee and poop diapers, and will be 2 weeks old tomorrow.