When you have a new child, you have only one priority in life, one that takes precedence over procuring food, finding a job, or anything else: getting the child to sleep through the night. Everything you do with a baby beforehand—feeding it, putting it on a schedule, repeatedly throwing the baby up in the air and then catching it so that the thing gets really tired—is geared toward achieving that moment. Before the child sleeps through the night, you aren't a human being. You're just a lifeless sack of beef constantly waiting for a clean night through. After that moment, you again become fully functional, as close to normal as normal can be.
The problem is that there's no guarantee of when that moment will arrive. I have three kids, and among them there was absolutely no consistency as to when each child began sleeping through the night. My first kid started sleeping through the night at 10 weeks old, which is very early and served as an irrational source of pride for me even though it was dumb luck. Parents constantly ask each other if their babies are sleeping through the night, and if your baby is sleeping through the night and someone else's isn't, then that parent is a fucking failure and you get to passive-aggressively gloat in front of them. "Oh, wow, your kid is a year old and not sleeping through the night yet? Is she needy? Brain damaged? She might be both. All I know is I got eight solid hours last night. Fucking CRUSHED that sleep, bro! She falls asleep at 7 and wakes up at 7. Now let me take a picture of you looking crazy jellz!"
I assumed our next kid would take only 10 weeks to sleep through, but that wasn't true at all. It took my second kid a year to sleep through the night, even though I don't think we did anything different. You're allowed to start sleep training a baby at around four to six months old. That is, you're allowed to ignore them when they cry for food in the middle of the night because THIS IS NOT A FUCKING 7-11, KID. YOU CAN'T JUST EAT WHENEVER YOU WANT. This is a process called Ferberization and it almost always works, provided you have the STEEL BALLS to not go running to your precious child the second he or she starts crying.
(NOTE: There are coddling parents and parenting experts who believe that you should ALWAYS respond to your child's crying, and you should ALWAYS be able to determine the child's needs, and you should feed the child ALL NIGHT LONG, and it shouldn't be a problem because the child should be IN YOUR BED anyway, and if you object to any of this or it doesn't work, it's because you don't care enough to treat your child right, and you are damaging your child and ruining its emotional balance for life. These people are insane and must be lashed.)
The problem is that, if the child cries long enough, you become tempted to just feed the thing and get it over with, so that you can go back to bed instead of listening to it wail for hours and hours. But if you do that, then the baby become a fat and entitled GLORY BABY who expects you to make with the six warm ounces at 3 a.m. forever after. The longterm effects are devastating, and so you have to have willpower, or soundproof walls. Soundproof walls would probably do nicely.