I typically don't expect them to sleep for more than 6 hrs co until they're about 6 months old. A lot goes into babies being able to sleep long stretches, multiple REM cycles, co. They have to be able to self soothe and put themselves back to sleep. They also have to have big enough digestive systems to be able to process enough calories during the day to not need calories input at night. We start our bedtime routine with them at 7pm and they're asleep by 8-8:30. We do bath, lotion, pajamas and a feed. It takes a little time to soothe them to sleep but there's a build up of sleep pressure so they go down pretty easily. They've also gotten used to the whole process since we've been doing it nightly since 4 weeks or so. I wake them for a dream feed around 11:30pm where they'll eat and fall back asleep pretty fast. Takes about 30-45 mins for both. Then they'll get up again between 2- 4am hungry so I'll feed them. Then they wake around 6 or 7 for the day. On a good night, my REM cycle will match theirs and the wake ups won't be too jarring but if they stagger their wakes then I might be up for many co hours with no or little sleep in between. Up until recently, my husband and I were doing overnight feeds together but recently we changed to only me doing overnight feeds since they're getting faster and easier to settle. I do overnights and then he takes over around 6am. I go sleep until 9 or so for a guaranteed full REM cycle. Between the two of us, I handle broken up sleep and overnight grogginess way better than he does so that's why I do the overnights. I hope that helps. If you have more questions, let me know ❤️