How much do you layer up newborn in winter?

Typically its however many layers you are wearing. If you have pjs and 2 blankets, your baby will be most comfortable in 3 layers also. Just watch for his signals to see if he's comfortable (you'll know if he's not). Swaddling vs sleeper sacks really depends on the baby. both are safe, but some kids prefer movement and space, others sleep better if they are swaddled up. Just do which ever you are most comfortable with, or you can try both and see what works best for you!