do I really need to wake my newborn every 2-3 hours to eat?

Aryana • Due November 11th , 2016 ♡♡
So at the hospital they told me my newborn needs to eat every 2-3 hours. So since then I've been doing this every night , other than some times we both accidentally over slept... I've seen and heard many people say that they never did this, and they just let their newborn wake them up when they r ready to eat (by crying) my baby doesn't have any weight problems.. she had lost 10 ounces the first week we were home because she wasn't latching right but that's all fixed now... so do I really need to wake up every couple of hours to feed her if she's not waking up herself? Usually she doesn't wake up to eat until 4 or 5 hours.. (noticed this on the times I overslept. I freaked out cause it had been so long but she never woke up or cried and was sleeping so peacefully but I woke her up to eat..) 
I'm just so exhausted all the time , only getting a couple hours of sleep at a time.. but if I need to continue doing this I will... just wanna hear yalls thoughts
My baby girl is 17 days today