How many sleepers do I need?

Megan

Hi - I’m a FTM due 1/12/21. How many sleepers do I need in newborn size and 0-3 months? Also how many onesies do I need? I’ve heard you want to dress your baby in one additional layer than what you need, so I plan to layer a long sleeve onesie underneath everything.

I live in the suburbs of Chicago so it’ll be cold the first few months of babies life. Thanks!