Your Freezer Stash
You probably don’t need one.
But even if you’re going to be away from baby (say, you’re going back to work) you don’t need to have a ton of ounces stored. Because what you pump while you’re away from baby will replenish what baby eats during that time.
If you are nursing (as in: you aren’t an exclusive pumper) a good practice is to pump while you and baby are away from each other and nurse when you are together. That way, the milk you pump can be dedicated specifically for when you are apart.
If you pump too much because of concern over your freezer stash, especially in the early days, you could create an oversupply, which sounds great but comes with its own set of issues (like propensity to plugged ducts).
So, you can store enough for a couple of days away from baby, but don’t freak out if you aren’t filling your freezer to the brim. If your supply matches baby’s needs and you don’t make a ton of extra milk, that’s awesome