I am not referring to 'parts' as ratios are obviously not vague if measured properly.
Juice of one lemon.
Juice of half a lime
A splash of coke.
I constantly see these in posts and even books where everything from a bottle is measured to the nearest ml.
How juicy is the orange, how large the lime, how much white is in the egg?
I know that some books give a rough indication of these measurements in a quantitative table at the back, but what is so hard about giving absolutes rather than relatives?