I think it's 24hrs but not sure.
I know we're meant to make up each feed fresh but my health visitor has basically told me that that ruling is based on research where they were testing bottles that we being kept in unsanitary conditions.
I actually think it's still ok after 24hrs but i'm not sure.
my lovely little girl varies between 15 and 25 oz a day, partly cos she's mixed feeding, so obviously if I end up wasting a lot of formula on the days where she only has 15, cos I always make up 30 at the start of the 24hrs (30 because even when she has 25oz, she'll often leave an oz here and there)
the new improved aptamil is even more bloody expensive so less waste would be good. thanks