When my kids were babies, they slept with us for the first 4 months or so, execpt on Friday nights, when DH and I wanted to be able to sleep in on Saturday.
Then we moved them to their own rooms. With my oldest, this lasted until she was about 22 months and we had newborn DS. Then we ended up "playing musical beds" - DD would start off in the "parents bed" w/ me, DH would look after DS and put him down to sleep about 10 or 11 (in his own bed) while DH went to slee in "DD's bed".
DS would wake at about 2 or or 3am, I would move DH to the bed w/ DD (who would wake and wail if she were alone) while I looked after DS and tried to get him to sleep again after nursing...
If DD was impossible to get back to sleep, I would knock on our helper's door at about 4:30 or 5am and say "pls. take him" while I tried to get a couple more hours sleep before going to work.
I am SO glad these days are now behind us.