Eh mama, honestly boleh je mixed feeding tanpa perlu tunggu jarak masa tertentu, baby boleh minum susu ibu pastu terus susu formula, or sebaliknya, takde masalah. A few of my mum friends do this semua hari and their babies fine-fine je, tapi kalau baby ada reflux atau sensitive tummy, maybe boleh space out a bit untuk tengok macamana baby react. Best thing is check dengan your paediatrician sikit, especially if baby punya concerns, sebab dia tahu baby's specific needs better, some babies can handle mixed feeding without any breaks, some prefer a bit of spacing.