That is the absolute best way Aerolor…
I always buy a four pint bottle of milk. I use it until it smells and that’s maybe three days after it’s sell by date. I use the rest of the milk to make Soda bread or use it in cake mixture.
I have never suffered any ill effects and like to think l am generally healthy except for the usual ‘in the family’ inherited things.
I have frozen two single pints of milk in my freezer. There was some left over (not gone off) milk that l put in a plastic container and froze it to use in cakes.
There’s a saying, ‘You have to eat a peck of dirt before you die’. I firmly believe in that.
I use Soya milk Mups, the difference is the ones in the chilled section are short life and need to be kept chilled and the ones on the normal shop shelves are long-life Soya milk which can be kept out of the fridge for days/weeks before they are opened …once opened they are kept in the fridge.
It wasn’t that OGF, just my play on words. 
You had written ‘Rubics’ and I changed it to Rubice as in Rubeice cubes
OK, I know it isn’t that funny.
I remember some years ago, a farmer was experimenting with freezing milk directly inside the cows. Of course, this meant that the cows themselves had to be frozen on a daily basis. At a set time each day, there was this woman in big glasses who would come round and defrost them. Now, what was her name?
Ah yes, that’s it… Thora Hird
A 4pint container of green top milk lasts us about 6 days. It stays in the fridge.
Ditto, Percy 
If your milk goes off after only 3 days there’s something wrong with your fridge! They are only covering their backsides by saying consume within 3 days, it’s fine!
If you have the room, decant enough to last you a few days and freeze the rest in the original container (I think someone may have already suggested that)
You can buy long life (UHT) cows milk in cartons that only needs refridgerating once opened. It’s fine, doesn’t taste that much different.
Thanks for all the advice Swimmy, will bin it after 3 days. If there’s no shortage, that’s made me feel a tad better.
Aerolor, a few years ago I kept feeling vaguely unwell after drinking my cuppas and thought I was going to have to give tea up again. (I went through a few years being unable to stomach it).
Anyway, whilst leaning idly against the units waiting for the kettle to boil, I started reading the milk container and was gobsmacked it said use within 3 days. :surprised:
I’d go well over the 3 days with my pint.
I’m quite sensitive to foodstuff. You get folk who can eat/drink something that’s ‘just on the turn’ and it never affects them.
Me, well… an entirely different story :shock: 
Thanks Jazzi, haven’t seen those. They look so much better than those old rigid ice cube trays we all used to have.
Don’t put it in a test tube
Yes, I found it confusing at first Mags, with some chilled and some not, but as you say, there is a difference in some cartons so I have to look what I’m doing.