Well, I don’t have kids, but I have five (soon to be six) younger siblings, so…
My mom doesn’t trust cribs, so she sleeps with each of her children until they were about a year and a half old. Why? So she didn’t have to worry about getting up to breastfeed or us suffocating in the middle of the night. After us kids “came of age” we would sleep in our own bedrooms; our parents, of course, check up on us until we are about three.
Due to lack of space, some of my siblings have to sleep with one another, so… Yeah. ^-^