Mix your milk! If not, fat & caloric content can differ a lot which affects metabolic processes & weight gain.
Layering milk - yes, you can!
Milk from different sessions can be mixed into one container but cool to same temperatures before mixing.
How to thaw human milk:
In fridge overnight
Run it under warm water
Big container of warm water
Waterless warmer
Warm it slowly
20 mins in warm water
Need a cheat sheet? I will create my own reference guide soon! For now, use this one and share with clients, partners or daycare providers.