Should I wake my baby?

Heather
So, I need some opinions from other mammas. I am a FTM to a wonderful baby boy. He usually naps a few times during the day and me and my boyfriend usually put him to bed by 8 or 9 at the latest. Ever since he was a month old he would sleep for long stretches of the night ranging around 5-7 hours straight. I used to wake him up by the 3rd hour to feed then put him back to sleep but lately I've been letting him sleep for 7 hours straight then waking him to feed because I'm so tired! I've talked to my mom about it and she says with her kids she would just let us all sleep until we woke up ourselves to eat. I'm just worried that if I do that he will go too long without waking up and get dehydrated. What do you ladies think? Wake the baby or let him sleep?