expressing - how much is enough for a feed?

[MrsMcQueen]

I'm going to an engagement party tomorrow and I'm trying to express milk for my 8 week old DS. But its the first time I've tried to do it and not sure how much he'll need for a feed. Also, is it ok to mix milk I've expressed from today with milk from tomorrow or does it need to be kept separate?

How long does your baby feed for when he is full? Pump for that long, both sides combined and that's probably a good rule of thumb. You can mix, as far as I remember, as long as it's all refrigerated. But might you not want to have more than one feed to give him? There's plenty of online guidance about how long it can be kept in the fridge/frozen.

my little baby is 11 weeks old

she had 1 BM bottle a day since 5 weeks old and at that point drained 6oz (sometime id end up topping her up with boob after too)

since 9 weeks she has had 7oz, and again almost always drains the lot, tonight was the first time she's needed a booby top up after 7oz.

Id leave 7oz to be sure.
(you could always leave 4oz, and 2 different containers with 2oz in each, so that if 4 (or 6 oz) is enough, you have some extra spare to freeze for next time

(oh and when i pump i only get 1.5 - 2oz per breast, and i know she takes more than 3 / 4 oz per feed)

some people can pump loads, others cant get as much

Lots of information on pumping and storing milk here.

HTH