Sleep sack ?

Hannah🍌 • 9/6/19

My baby was sleeping in the swaddle up love to dream. A week ago during the day she doesn’t use it but at night she does. I’m doing that so she can transition easy when she doesn’t have to use it at all

So my question is what do I use at night so she stays warm? Is she too old to use the sleep sack. With the arms out. She is almost 4 months.

Wanted to know what other moms are doing when they sleep without anything