There seems to be some confusion amongst the replies about whether the OP meant milk still in the factory sealed container, or milk after the container’s been opened and the milk partly used.
IMO / IME there’s a big difference in shelf (fridge shelf that is) life between those two scenarios.
IME open milk is a week to 10 days before it starts getting iffy and another 3-4 sliding from iffy towards yucky. Sealed milk seems to be good for about 3 weeks pre-opening before it starts to go. But goes quickly once opened.
I also have a pretty robust stomach that deals well with iffy food. Unlike some folks who suffer a lot more from a lot less.