If your 3-year has been sleeping through the night, maybe it's only been 3 months or 6 months or hopefully a year, and now you want to sleep coach your 6-month old. A lot of parents are scared. Oh no. We finally got our 3-year old sleeping well, and we're frightened to sleep coach the baby, because now every time they wake up, they're going to wake up the older one and we're going to go back into this same problem that we have, which inadvertently what the parents will do is they'll rush in and pick up the 6-month old to quiet them so that they don't wake up the 3-year old, and then they create a sleep problem with the baby that they then have to address. So I'll tell parents that, you know what, I don't want you to worry about it, because there's no way that we can guarantee that the 3-year old will wake up. Again, I'd rather you just divide and conquer. So one of you go into the baby. The other one just go into the 3-year old and say, it's okay sweetie. We're teaching baby how to sleep through the night. Night-night. Don't lie down with them and start your old crutch. Reassure them and leave. And let's say you're alone. And you don't have two parents to go in and divide and conquer and the baby wakes up in the middle of the sleep coaching at night. I would go into the 3-year old and say, I know the baby's awake - because hopefully you've already told them that you're going to sleep coach the baby. And everything's fine. I'm going to go check on the baby. And then just preempt any problems from there and then go attend to the baby.