Best advice ever given to me was "sleep when your baby sleeps. At least for the full first year"
So I did exactly that. When ds napped I did too, when he was out for the night I was too. I know it gets hard if you are working, but when people ask if they can help say yes and tell then what to help with, the dishes, the laundry, anything so when you are lying down your not thinking of using that time for anything else but sleep and closeness to your baby.
My ds it 6 and I still go to bed with him at 8:30pm. I wake up much earlier to do the things I need to, but I so much enjoy getting to fall asleep next to him, and some nights my DP will wake me to sleep with him, but not very often. I sleep much better with ds, and so does ds.