That's another problem: you can re-label all you want, but the glasses, packings and tins are still the same size. Now if you are confronted with remembering 1

That's another problem: you can re-label all you want, but the glasses, packings and tins are still the same size. Now if you are confronted with remembering 1 pint or fivehundredsixty... that compilcated other number, you will always opt for the easier one. Weather it's about remembering or mentioning. For the same reason we have more easily rememberable increments of 250ml, 330ml and 500ml.