Pumping and storing

KM
My little one is headed to daycare soon as I head back to work. He's a trooper with bottles, and I have a stash of milk in the freezer and will pump at work but still BF whenever I am home. 
My question is about storage--in what volume should I store milk?  If a feeding is around 3oz, store in that volume so it's easy to thaw and heat a single serving?  Or larger volumes so one bag works for several feedings or has enough for when he eats more than 3oz?
What are other working/pumping moms doing?